JP2014036544A - Method for controlling electrostatic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling an electrostatic actuator, capable of reducing electrostatic charge hindering moving operation of a mover without increasing a size of a device.SOLUTION: A method for controlling an electrostatic actuator is disclosed. An electrostatic actuator 100 to which this method is applicable comprises a stator 1 and a mover 2, a plurality of electrodes 3 for making the mover move being provided in the stator. In the method, when making the mover move, for example, movement signals respectively with mutually different four phases are supplied to the plurality of electrodes, and when the movement signals are not supplied, an AC static charge elimination signal of which a voltage changes to be alternately negative and positive with the same waveform and which reduces the charge amount of electrostatic charge generated in the stator and the mover, is supplied to each of the plurality of electrodes, thus reducing the electrostatic charge, and a signal having decreasing positive and negative voltage times where a positive voltage time and a negative voltage time decrease together due to gradual increase of frequency, attenuation of pulse, or the like, or a signal of which a voltage is attenuated, is used as the static charge elimination signal.

Description

  The present invention relates to a method for controlling an electrostatic actuator.

Conventionally, an electrostatic force that has a stator and a mover and induces a charge on the mover by giving a move signal to a plurality of electrodes provided on the stator and acts between the stator and the mover by this charge. Thus, an electrostatic actuator that moves the mover relative to the stator is known.
However, as schematically shown in the partial enlarged cross-sectional view of FIG. 8, the conventional electrostatic actuator 200 generates static electricity due to frictional charging in the stator 1 and the moving element 2 due to friction between the stator 1 and the moving element 2. Then, the mover 2 sticks to the stator 1 and stops, or the movement of the mover 2 becomes slow, and the smooth movement of the mover 2 is hindered. Static charge is likely to occur when the environmental potential is biased or dry. The figure shows an example in which the stator 1 is charged with negative static electricity and the mover 2 is charged with positive static electricity. The static electricity of the stator 1 is drawn on the surface of the stator 1 facing the mover 2. The static electricity of the mover 2 is drawn on the opposite side of the face of the mover 2 facing the stator 1.
Thus, electrostatic actuators that prevent charging have been proposed so that the moving element can be smoothly moved (Patent Documents 1 and 2).

  In the electrostatic actuator of Patent Document 1, in an electrostatic actuator in which an electrode for inducing charges is provided not only in the stator but also in the moving element, the moving electrode moves in the stator and moving electrode. The signal to be applied to is divided into the first half and the second half, the first half is given a movement signal, and the second half is given a waveform signal that cancels the positive and negative bias of the voltage of the movement signal. We have proposed a technology that prevents the generation of charges due to the bias. Patent Document 1 also proposes a technique for removing charge by applying a signal in which positive and negative are alternately switched with voltages having different polarities to electrodes facing each other of the stator and the moving element when the moving element is stopped. .

  In the electrostatic actuator disclosed in Patent Document 2, a portion where the stator and the mover face each other, for example, a portion of the stator that the mover faces, such as an opposite surface of the stator that faces the mover, contacts the mover when moving. Thus, an electrostatic actuator provided with a static eliminating brush has been proposed.

In Patent Document 3, although it is not an electrostatic actuator, as an antistatic measure for various members, a conductive material such as a resin in which carbon fiber is kneaded is used as a constituent material of the member, or a conductive polymer is applied on the surface. A technique has been proposed in which a material subjected to a prevention treatment is used to give a certain degree of conductivity to the member itself so that it is difficult to be charged.
Patent Document 4 proposes an electrostatic actuator using ionic wind as means for giving positive and negative electric charges for driving to a moving element for moving operation, although it is not static elimination of electrostatic charging.

JP-A-9-238482 JP-A-6-121549 JP 2006-80458 A JP-A-4-75483

However, the antistatic measure of Patent Document 1 is an antistatic measure that is effective only for an electrostatic actuator in a form in which an electrode for inducing charge needs to be provided not only on the stator but also on the mover. Cannot be used for the electrostatic actuator in the form of being provided on the stator without being provided. Moreover, the electrostatic actuator in the form in which the electrodes are provided on both the stator and the mover has the disadvantage that the structure is complicated compared to the form in which the electrodes are provided only on the stator side, and the cost is high. It cannot be applied to applications where the proper structure is not suitable.
As a result of using the static elimination brush, the antistatic measure of Patent Document 2 may cause a new problem that scratches or brush scraps from the static elimination brush adhere as dust to the opposing surface of the stator or the mover. is there. Moreover, when an electrostatic actuator is used as an exhibit, the appearance is impaired.

The antistatic measure of Patent Document 3 is a measure for various general members. However, when this is applied to an electrostatic actuator, the surface resistivity of the slider surface is more than the surface resistivity preferable for the electrostatic actuator. It becomes small and cannot be applied to an electrostatic actuator. This is because the surface resistivity of the mover surface needs to retain a certain amount of insulation because the charge induced for the movement needs to be held until the next charge is induced.
Although it is conceivable to use the ionic wind used in Patent Document 4 for antistatic purposes, the use of the ionic wind requires an ion generator and a blower, which increases the size of the electrostatic actuator and increases the weight. Moreover, it leads to high cost, which is not preferable.

  Therefore, an object of the present invention is to provide a method for controlling an electrostatic actuator that can reduce the charging that hinders the moving operation of the moving element without increasing the size of the apparatus.

The electrostatic actuator control method according to the present invention has the following configuration.
(1) A stator and a mover disposed on the stator are provided, and a movement signal for moving the mover in a direction parallel to the opposing surfaces of the stator and the mover is sent to the stator. A method of controlling an electrostatic actuator that supplies to a plurality of electrodes provided,
Control of an electrostatic actuator that supplies an AC static elimination signal that reduces the amount of charge generated in the stator and the moving element to each of the plurality of electrodes when the movement signal is not supplied to the plurality of electrodes. Method.
(2) The electrostatic actuator control method according to (1), wherein the static elimination signal is a signal in which a voltage positive / negative time which is a time for applying a positive voltage and a time for applying a negative voltage decreases with time.
(3) The static elimination signal is a signal in which the maximum value of the absolute value of the voltage in the voltage positive / negative time, which is the time to apply a positive voltage and the time to apply a negative voltage, decays with time. Method for controlling the electrostatic actuator.

  According to the electrostatic actuator control method of the present invention, it is possible to reduce charging that hinders the moving operation of the moving element without increasing the size of the apparatus.

The side view (a) which shows an example of the electrostatic actuator which can apply one Embodiment of the control method of the electrostatic actuator by this invention, and a partial expanded sectional view (b). The fragmentary expanded sectional view which illustrates the electrostatic actuator which has the electrode corresponding to the four-phase type movement signal in one embodiment of the control method of the electrostatic actuator by the present invention. The figure which shows an example of a 4-phase type movement signal. The figure which shows an example (voltage positive / negative time reduction | decrease) of a static elimination signal. The figure which shows an example (voltage attenuation | damping) of a static elimination signal. The block diagram which shows an example of the power supply part which can supply a movement signal and a static elimination signal. The top view which shows an example which provided the electrode in 3 area | regions and 3 area | regions of a stator. The partial expanded sectional view which shows an example of the conventional electrostatic actuator.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are conceptual diagrams, and the scale relationships, aspect ratios, and the like of components may be exaggerated.

[Summary]
FIG. 1 shows an example of an electrostatic actuator to which an embodiment of the method for controlling an electrostatic actuator of the present invention can be applied. FIG. 1 (a) is a side view and FIG. 1 (b) is a partially enlarged sectional view. .
The electrostatic actuator 100 shown in the figure includes a stator 1 and a mover 2, and a charge signal is supplied to the mover 2 by supplying a move signal Sm to a plurality of electrodes 3 provided on the stator 1. The electrostatic force acting between the stator 1 and the movable element 2 due to this electric charge causes the movable element 2 to move in a direction parallel to the opposing surfaces of the stator 1 and the movable element 2. Can be moved to.
In the electrostatic actuator 100 shown in FIG. 1, the moving element 2 is depicted as being disposed on the stator 1, and when the downward direction in the drawing is the ground, in other words, the downward direction in the drawing is the direction of gravity, Literally, the mover 2 is arranged above the stator 1. However, in the present invention, the meaning of “mover arranged on the stator” means that the mover 2 is located farther from the direction of gravity with respect to the stator 1 as the positional relationship between the mover 2 and the stator 1. It is not limited to the positional relationship to be arranged, and any positional relationship where the opposing surfaces of the stator 1 and the moving element 2 are in contact with each other may be used. For example, the opposing surfaces of the stator 1 and the moving element 2 are in the direction of gravity. The positional relationship may be a vertical plane.

  The size of the facing surface of the mover 2 that faces the stator 1 is smaller than the size of the facing surface that allows the stator 1 to face the mover 2. As a result, the mover 2 can move in a direction parallel to the facing surface that allows the stator 1 to face the mover 2. For example, the size of the stator 1 is a rectangle having a length of 1000 mm and a width of 600 mm, and the size of the mover 2 is a square having a length of 500 mm and a width of 500 mm.

  Each of the plurality of electrodes 3 has conductivity formed on or inside the substrate, and a known material, shape, and arrangement can be adopted. Each of the plurality of electrodes 3 is not particularly limited as long as it has conductivity, and a metal such as copper, silver or gold or an alloy thereof may be used, and a transparent material such as ITO (tin-doped indium oxide). May be used. Further, for example, they may be linear and extend in a direction parallel to each other and perpendicular to the paper surface. Further, for example, each of the plurality of electrodes 3 may be arranged at an equal interval such as a 0.3 mm pitch.

As the stator 1 and the mover 2, known ones can be used. The stator 1 only needs to have a substrate and a plurality of electrodes 2 formed on or in the substrate, and protects the electrodes as described in JP 2011-205786 A. You may have a sliding structure film | membrane which reduces friction with a cover film or the moving element 2. FIG. For example, the stator 1 is an ultraviolet curable acrylic film having a 12 μm thick insulating coating on the opposite surface in contact with the movable element 2 side of a polyimide flexible printed circuit board having a thickness of 25 μm on which a plurality of electrodes 3 are formed. It is possible to use a sliding structure film formed by coating with a base resin paint. A transparent material such as ITO (tin-doped indium oxide) can be used for the plurality of electrodes 3.
As will be described later with reference to FIG. 2, the movement signal Sm and the charge removal signal Se are supplied to the plurality of electrodes 3 through the bus line 4 and the connection terminal 5. The connection terminal 5 is connected to a power supply unit 6 to be described later at least when the electrostatic actuator 100 is driven, so that the movement signal Sm and the charge removal signal Se are supplied to the plurality of electrodes 3. By connecting the power supply unit 6 via the connection terminal 5, the power supply unit 6 can be used in common for different stators 1.

The mover 2 only needs to have a dielectric, and may have a resistor layer. For example, use one having a resistor layer coated and formed with an ultraviolet curable acrylic resin paint containing ATO (antimony-doped tin oxide) particles on one side of an insulating substrate made of a polyethylene terephthalate film having a thickness of 50 μm. Can do. The surface resistivity of the resistor layer is, for example, 10 ⁹ to 10 ¹⁴ Ω / sq (also referred to as Ω / □), preferably 1 × 10 ^{12 to} 9 × 10 ¹² Ω / sq. Even if it is smaller than this range or larger than this range, the smooth movement operation of the moving element 2 may be impaired. This is because smooth induction of charge and proper retention of the induced charge until the next charge is induced are realized.
The resistor layer can be provided, for example, on the surface opposite to the surface of the movable element 2 facing the stator 1.

  Furthermore, in the embodiment of the control method of the electrostatic actuator, when the movement signal Sm is not supplied to the plurality of electrodes 3 to the electrostatic actuator 100, a voltage with the same waveform is applied to each of the plurality of electrodes 3. Are alternately switched between positive and negative, and the charge can be reduced by supplying an alternating charge-removing signal Se that reduces the amount of charge generated in the stator 1 and the mover 2.

[Moving signal Sm]
As the movement signal Sm supplied to the plurality of electrodes 3 provided in the stator 1, various types of conventionally known methods can be employed. For example, a method of supplying a plurality of phase movement signals Sm such as a two-phase method, a three-phase method, and a four-phase method can be employed.

  The electrostatic actuator 100 to which one embodiment of the electrostatic actuator control method shown in the partially enlarged cross-sectional view of FIG. 2 can be applied can be operated by a four-phase movement signal Sm. For this reason, the plurality of electrodes 3 included in the stator 1 correspond to each phase so that the electrostatic actuator 100 shown in FIG. It consists of an electrode 3b, a plurality of electrodes 3c, and a plurality of electrodes 3d. These electrodes 3 are arranged at equal intervals in the order of electrode 3a, electrode 3b, electrode 3c, electrode 3d, electrode 3a, electrode 3b, electrode 3c, electrode 3d,. Then, each of the plurality of electrodes 3a, the plurality of electrodes 3b, the plurality of electrodes 3c, and the plurality of electrodes 3d has four-phase signals of different phases, a movement signal Sm1, a movement signal Sm2, and a movement as the movement signal Sm. A signal Sm3 and a movement signal Sm4 are supplied. Therefore, the plurality of electrodes 3a are connected to the bus line 4a to which the movement signal Sm1 is supplied, the plurality of electrodes 3b are connected to the bus line 4b to which the movement signal Sm2 is supplied, and the plurality of electrodes 3c are connected to the movement signal Sm3. The plurality of electrodes 3d are connected to the bus line 4c to which the movement signal Sm4 is supplied.

The bus line 4a is supplied with the movement signal Sm1 from the connection terminal 5a, the bus line 4b is supplied with the movement signal Sm2 from the connection terminal 5b, and the bus line 4c is supplied with the movement signal Sm3 from the connection terminal 5c. 4d is supplied with a movement signal Sm4 from the connection terminal 5d.
In this specification, when the electrodes 3a, 3b, 3c, and 3d for different phases are collectively referred to as “electrode 3”, they may be simply referred to as “electrode 3”.
Similarly, when the bus line 4a, the bus line 4b, the bus line 4c, and the bus line 4d are collectively referred to, they may be simply referred to as “bus line 4”.
Similarly, when the connection terminal 5a, the connection terminal 5b, the connection terminal 5c, and the connection terminal 5d are collectively referred to, they may be simply referred to as “connection terminal 5”.

FIG. 3 is an example of the movement signal Sm1, the movement signal Sm2, the movement signal Sm3, and the movement signal Sm4 as the four-phase movement signal Sm. Each of the movement signal Sm1, the movement signal Sm2, the movement signal Sm3, and the movement signal Sm4 is a rectangular wave with the same voltage, and the maximum value of the positive and negative absolute values is equal. The voltage is, for example, 800 Vpp peak-to-peak. The movement signal Sm1, the movement signal Sm2, the movement signal Sm3, and the movement signal Sm4 are out of phase by a quarter period in this order. Further, each of the movement signal Sm1, the movement signal Sm2, the movement signal Sm3, and the movement signal Sm4 has a duty ratio of 50%.
In the present invention, the duty ratio of the movement signal Sm is not necessarily limited to 50%.

[Static elimination signal Se]
The static elimination signal Se is an AC signal that reduces the amount of charge generated in the stator 1 and the mover 2 in each of the plurality of electrodes 3 when the movement signal Sm is not supplied to the plurality of electrodes 3. The charge can be reduced by the charge removal signal Se.
The charge removal signal Se is a signal that forcibly causes positive charge and negative charge alternately and attenuates the positive charge amount and the negative charge amount with time. Even if a positive charge and a negative charge are alternately generated, if a signal is added as it is without attenuating those charges, the charge will remain depending on the signal waveform added last. The signal is forcibly attenuated with time.

The neutralization signal Se may be always supplied when the movement signal Sm is not supplied, or may be supplied only for a part of the period, such as when neutralization is required when the movement signal Sm is not supplied. But you can.
Note that “occurs” of “occurs in the stator and moving element” means both states in which static charge may occur but static charge has not occurred yet and static charge has been generated. including.

  The time for supplying the static elimination signal Se is not particularly limited, but for example 1 s is sufficient. If the static elimination signal Se with a frequency of 50 Hz is supplied during 1 s, the charging to be switched between positive and negative is repeated 50 times, and the charging amount decreases each time it is repeated.

  The static elimination signal Se is composed of a plurality of electrodes 3a, a plurality of electrodes 3b, a plurality of electrodes 3c, and a plurality of electrodes 3d corresponding to the four phases as shown in FIG. Even so, they are all supplied as signals having the same waveform (see FIG. 2). For this reason, the mover 2 is not moved by the static elimination signal Se. At this time, a signal having the same waveform but shifted phase may be supplied to the plurality of electrodes 3a, the plurality of electrodes 3b, the plurality of electrodes 3c, and the plurality of electrodes 3d for each phase. The mover 2 does not necessarily move just because a signal out of phase is supplied.

An example of the static elimination signal Se is shown in FIGS. The neutralization signal Sef illustrated in FIG. 4 is an example of a signal in which the positive voltage time and the negative voltage time are both decreased, in which both the positive voltage time and the negative voltage time decrease. Therefore, the static elimination signal Sef illustrated in FIG. 4 is also a signal in which the time for applying the positive voltage and the voltage positive / negative time, which is the time for applying the negative voltage, decrease with time.
The static elimination signal Sev illustrated in FIG. 5 is an example of a signal whose voltage is attenuated. Therefore, the static elimination signal Sev illustrated in FIG. 5 is also a signal in which the maximum value of the absolute value of the voltage in the voltage positive / negative time, which is the time for applying the positive voltage and the time for applying the negative voltage, attenuates with time.
The neutralization signal Sef illustrated in FIG. 4 and the neutralization signal Sev illustrated in FIG. 5 are both rectangular wave alternating currents having the same maximum absolute value of positive and negative voltages, and are signals having a duty ratio of 50%. The static elimination signal Sef illustrated in FIG. 4 is also a signal whose frequency gradually increases because the duty ratio is 50%.
By supplying the AC neutralization signal Se that alternately switches between positive and negative voltages, preferably at equal time, it is possible to reduce the charge amount while forcibly generating positive and negative charges alternately.
In the present invention, the static elimination signal Se is not limited to a rectangular wave. However, the rectangular wave as the charge removal signal Se has an advantage that the power supply unit 6 described later can be configured by a digital processing circuit.

When a resin film is used, such as the mover 2 made of a polyester resin film, since the film is generally easily charged with negative electrostatic charges, the static elimination signal Se supplied to the plurality of electrodes 3 on the stator 1 side. For example, a signal having a longer time during which the voltage is negative, a signal having a larger absolute value of the voltage when the voltage is negative, or a signal having both of them may be used.
Although it does not correspond to the static elimination signal Se of the present invention, it has a constant frequency, a constant voltage, and a frequency that is higher than the frequency of the movement signal Sm, such as 1 kHz, at a high frequency that does not catch up with charging induction and cannot move. If an alternating current signal with a constant duty ratio is supplied, the charging bias with the positive and negative static electricity generated in the stator 1 and the moving element 2 can be eliminated. However, the charging itself can smoothly move the moving element 2. It cannot be reduced to the extent that it can be recovered, and is inferior to the static elimination signal Se according to the present invention.

The method of decreasing the voltage positive / negative time and the method of voltage decay may be, for example, geometrical series, geometrical series, stepwise, etc., and there is no particular limitation.
In this specification, when the static elimination signal Sef in which the voltage positive / negative time decreases and the static elimination signal Sev in which the voltage attenuates are collectively referred to simply as the “static elimination signal Se”.

(Static elimination signal Sef)
The static elimination signal Sef for decreasing the voltage positive / negative time shown in FIG. 4 may be constant. For example, the voltage is constant at 800 Vpp, and after increasing the frequency from 10 Hz to 1 kHz for the first time, to each of the plurality of electrodes 3. Stop supplying all of them at once. Thereby, electrification can be reduced.
Further, the static elimination signal Sef of FIG. 4 in which the voltage positive / negative time decreases may have a constant frequency. For example, the frequency is constant at 50 Hz, and the voltage is sequentially in one cycle, positive for a finite time, zero for a finite time, negative for a finite time. The time of the positive voltage and the time of the negative voltage may be decreased by displacing from zero for a finite time. In the rectangular wave, in one cycle, the pulse width when the voltage is positive and the pulse width when the voltage is negative both decrease and the time of zero volt gradually increases.

  The reason why charging is reduced by the static elimination signal Sef is considered as follows. That is, the static elimination signal Sef is a signal in which the voltage is alternately switched between positive and negative, and in order to supply all of the plurality of electrodes 3, the stator 1 and the mover 2 are arranged so that the opposing surfaces of the plurality of electrodes 3 are Positive charging and negative charging are alternately repeated. However, since there is a time constant for charging, charging is not instantaneously positive or negative according to the rising of the waveform of the rectangular wave of the static elimination signal Sef. For this reason, as the time of the positive voltage and the time of the negative voltage in one cycle of the static elimination signal Sef decreases, sufficient time for charging positively or negatively cannot be secured, and the charge amount decreases. become. As a result, by supplying the static elimination signal Sef for decreasing the voltage positive / negative time, the positive charge and the negative charge are alternately repeated, and the charge amount when positively charged and the charge when negatively charged are negatively charged. The amount of charge will decrease. As a result, it is considered that the charging converges to a substantially neutral state where the amount of charge is less than the amount of charge that hinders the movement of the moving element 2.

The voltage of the static elimination signal Sef is not particularly limited as long as each of the positive voltage and the negative voltage is higher than a voltage at which charging can occur. That is, the static elimination signal Sef is a signal for decreasing the voltage positive / negative time in which both the time of the positive voltage that can cause charging and the time of the negative voltage that can cause charging are decreased. The voltage that can cause charging is an absolute value, for example, preferably 100 V or more. This is because if it is less than this, the electric charge may not be sufficiently generated.
From the standpoint that the neutralization signal Se can be easily supplied to the power supply unit 6 that supplies the movement signals Sm to the plurality of electrodes 3, it is preferable that the voltage is not so different from the movement signal Sm even with a large voltage. For example, in the static elimination signal Sef in which the voltage positive / negative time as the static elimination signal Se decreases, the effect is obtained at 1000 Vpp.

Voltage positive time or voltage negative time (total of voltage positive time and voltage negative time corresponds to one cycle) within one cycle before the start of voltage positive / negative time reduction of the static elimination signal Sef in which the voltage positive / negative time decreases. In the case of a signal with a duty ratio of 50%, it corresponds to 1/2 of the reciprocal of the frequency.) Is not particularly limited, but for example, when the frequency is 1 Hz, 1 s is required for the first period. Minutes, the time required for static elimination increases. This is also acceptable if you have time. However, when it is necessary to finish the static elimination in 1 s, for example, it is preferable to start from the range of 10 Hz to 50 Hz in terms of frequency. That is, when the duty ratio is 50%, at a frequency of 10 Hz, the voltage positive time or the voltage negative time is (1 s / 10) × 0.5 = 50 ms, and at a frequency of 100 Hz, it is 5 ms.
The voltage positive time or the voltage negative time within one cycle after the voltage positive / negative time decrease of the static elimination signal Sef in which the voltage positive / negative time decreases can be expressed by the movement signal Sm in terms of the frequency viewed from the signal with a duty ratio of 50%. Is usually 1 to 10 Hz, and at most about 100 Hz, the speed at which charging cannot follow the change in voltage is 10 times the maximum frequency of the movement signal Sm, for example, 1 kHz or more. It is preferable to do. That is, when the duty ratio is 50% and the frequency is 1 kHz, the voltage positive time or the voltage negative time is (1 s / 1000) × 0.5 = 0.5 ms.
However, considering the point that charging becomes meaningless and power consumption is wasted even if the frequency is set too high, the voltage positive time or the voltage negative time at the end time should be determined. .
Note that the voltage of the static elimination signal Sef that decreases the voltage positive / negative time may be constant, but it is not essential that the voltage is constant. However, since gradually increasing the voltage is in the direction of increasing charging, a change that attenuates even if there is a voltage change is preferable. Further, although the frequency may be constant, since the frequency is attenuated in the direction of increasing the charge, a change that gradually increases is preferable even if the frequency changes.

(Static elimination signal Sev)
The neutralization signal Sev with which the voltage shown in FIG. 5 attenuates may have a constant frequency. For example, the frequency is constant at 50 Hz, and the voltage starts from 1000 Vpp and decreases to 10 Vpp. Stop supplying all of them at once. Since the square wave static elimination signal Sev having the same positive and negative absolute values is supplied, the maximum positive voltage at the start is 500V, and the maximum negative absolute voltage is also 500V. Thereby, electrification can be reduced.

  The reason why charging is reduced by the static elimination signal Sev is considered as follows. That is, the static elimination signal Sev is a signal in which the voltage is alternately switched between positive and negative. In order to supply all of the plurality of electrodes 3, the stator 1 and the mover 2 are arranged so that the opposing surfaces of the plurality of electrodes 3 are Positive charging and negative charging are alternately repeated. In addition, since the voltage is attenuated, by supplying the static elimination signal Sev, positive charge and negative charge are alternately repeated, and the amount of charge when positively charged and when the charge is negatively charged The amount of charge will decrease. As a result, it is considered that the charging converges to a substantially neutral state where the amount of charge is less than the amount of charge that hinders the movement of the moving element 2.

  The voltage at the start of the static elimination signal Sev whose voltage is attenuated before the voltage decay is not particularly limited, but may be approximately the same as the voltage of the movement signal Sm. This is because it is not necessary to use a component having a high withstand voltage for the power supply unit 6 to be described later for supplying the movement signal Sm as long as the voltage is the same as the voltage of the movement signal Sm. Therefore, the voltage at the start point before the voltage decay of the static elimination signal Sev can be set to, for example, 1000 Vpp. That is, the positive voltage is 500V and the negative voltage is -500V.

The voltage at the end of the neutralization signal Sev whose voltage is attenuated after the voltage attenuation does not have to be 0 Vpp. This is because electrostatic charging does not occur when the voltage is too low. Therefore, the voltage at the end point after the voltage decay of the static elimination signal Sev is 50 Vpp, preferably 20 Vpp, more preferably 10 Vpp or less.
As described above, the frequency of the static elimination signal Sev at which the voltage attenuates is preferably equal to or less than a frequency at which a time during which positive or negative charging can occur can be secured. For example, the frequency of the static elimination signal Sev may be approximately the same as the frequency of the movement signal Sm. Therefore, the frequency of the static elimination signal Sev is preferably set to 1 to 100 Hz, for example.
The duty ratio may be other than 50%. Any waveform may be used as long as the charge amounts of the positive charge and the negative charge that are alternately repeated are reduced as much as possible.
The frequency of the static elimination signal Sev whose voltage is attenuated may be constant, but it is not essential that the frequency is constant. However, since the frequency is decreased in the direction of increasing the charge, a gradually increasing change is preferable even if the frequency is changed.

[Power supply 6]
The configuration of the power supply unit 6 for supplying the movement signal Sm and the charge removal signal Se to the plurality of electrodes 3 of the stator 1 is not particularly limited. The power supply unit 6 only needs to be able to supply the movement signal Sm and the charge removal signal Se to the plurality of electrodes 3 of the stator 1. The power supply unit 6 can also be referred to as a drive signal output unit that outputs the movement signal Sm and the charge removal signal Se.
Hereinafter, an example of the configuration of the power supply unit 6 will be described. The power source unit 6 described here will be described as a static elimination signal Sef for decreasing the voltage positive / negative time in the static elimination signal Se in a form of gradually increasing the frequency with a constant duty ratio of 50%.

  FIG. 6 is a block diagram illustrating a configuration of the power supply unit 6. As the movement signal Sm, the power supply unit 6 shown in the figure is an example capable of supplying four-phase movement signals Sm having different phases. Furthermore, the power supply unit 6 shown in the figure is also an example having three systems so that a four-phase movement signal Sm can be independently supplied to each of the plurality of electrodes 3 in the three regions of the stator 1.

For example, in the case of the stator 1 illustrated in FIG. 7, the three regions of the stator 1 are a plurality of electrodes that can move the mover 2 relative to the stator 1 in the Y direction (vertical direction in the drawing). A region Y in which 3 is formed, and a region A and a region on the left and right sides of the region Y in which the movable element 2 can be moved relative to the stator 1 in the X direction (left and right direction in the figure) B, 3 regions.
The arrangement of the plurality of electrodes 3 divided into three regions as shown in FIG. 7 is such that when the mover 2 is moved relative to the stator 1 in the Y direction in the region A, the zigzag or biased movement in the X direction is performed. Thus, when the mover 2 is likely to be out of the region Y and enters the region A or the region B, it can be returned to the region Y.

Returning to the description of the block diagram of FIG. 6, in this figure, 6 is a power supply unit, 61 is a main body, 62 is a control box, and 63 is an AC adapter or a battery. In the main body 61, 64 is an automatic switching circuit / voltage conversion circuit, 65 is an I / F (interface), and 66 to 68 are high voltage 4-wire SW (switching) circuits.
The power supply unit 6 includes a main body 61, a control box 62, an AC adapter or a battery 63. The main body 61 receives supply of power from the AC adapter or the battery 63, operates in accordance with a command signal from the control box 62, generates a movement signal Sm and a charge removal signal Se, and supplies the movement signal Sm and the charge removal signal Se to the plurality of electrodes 3.
The power supply unit 6 sends a movement signal Sm or a static elimination signal Se from each of the high-voltage 4-wire SW circuits 66, 67, 68 of the main body 61 to each of the plurality of electrodes 3 in the region Y, region A, and region B of the stator 1. Can be supplied.

(Main unit 61 and AC adapter or battery 63)
The main body 61 operates by receiving power supplied from the AC adapter or the battery 63. The power supply from the AC adapter or the battery 63 is performed in the automatic switching circuit / voltage conversion circuit 64 of the main body 61. When the power can be supplied from both the AC adapter and the battery, the automatic switching circuit / voltage conversion circuit 64 disconnects the battery from the circuit and cuts off the power supply from the battery, and supplies power only from the AC adapter. To be performed.

(Control box 62)
The control box 62 is a controller that controls the moving operation of the moving element 2 and the charge removal in the electrostatic actuator 100. The control box 62 is provided with one or more operation means such as a push button switch, a changeover switch, a cross switch, and a joystick so that an operation by the operator is possible. When the operator operates one or more of them, the control box 62 outputs a command signal to the I / F 65 of the main body 61.

  The command signal includes, for example, start, end, advance, reverse, movement speed, static elimination, and the like. The start is a command signal for starting high voltage output from the + high voltage generation circuit and the −high voltage generation circuit, and the end is a command signal for stopping high voltage output from the + high voltage generation circuit and the −high voltage generation circuit. Forward movement is a command signal for moving the moving element 2 forward, and backward movement is a command signal for moving the moving element 2 backward. The moving speed is a command signal that determines the moving speed of the moving element 2 and is also a command signal that determines the frequency of the moving signal Sm. When the moving speed is increased, the command signal is set to a higher frequency, and when the moving speed is decreased, the command signal is set to a lower frequency.

(Operation of the main body 61)
The operation of the main body 61 can be controlled by the operator operating the control box 62. For example, it is possible to control the moving speed, moving direction, static elimination, etc. of the moving element 2 by operating the control box 62. When the operator operates the control box 62, a command signal is output from the control box 62. This command signal is input to a CPU (central processor unit) which is a data processing unit of the main body 61 through the I / F 65 of the main body 61. Based on the input command signal, the CPU of the main body 61 outputs a signal for determining the operation of each part (see FIG. 6) of the main body 61 to each part. When each part operates according to the signal, the main body 61 outputs a movement signal Sm or a static elimination signal Se.
Each part of the main body 61 operates by receiving power supply from the automatic switching circuit / voltage conversion circuit 64. For example, the CPU is supplied with a constant voltage and a constant voltage.

The positive and negative voltages of the movement signal Sm and the static elimination signal Se are determined by voltages output from the + high voltage generation circuit and the −high voltage generation circuit. The high voltage generation circuit generates a positive voltage and outputs it to the high voltage 4-wire SW circuits 66, 67, 68. The high voltage generation circuit generates a negative voltage and outputs it to the high voltage 4-wire SW circuits 66, 67, 68. To do.
Here, the + high voltage generation circuit can generate a positive voltage up to + 900V, and the −high voltage generation circuit can generate a negative voltage up to −900V.
The CPU of the main body 61 performs necessary data processing based on the command signal from the control box 62, and generates a voltage value to be output to the + high voltage generation circuit and the −high voltage generation circuit via the voltage decoder. Output to the circuit and the high voltage generation circuit. The voltage value is constant over time when the signal is a movement signal Sm. However, when the signal is a static elimination signal Sev whose voltage decays as the static elimination signal Se, the voltage value decays with time and the static elimination signal whose voltage positive / negative time decreases as the static elimination signal Se. In the case of Sef, the time is constant.
In addition, the CPU of the main body 61 performs necessary data processing based on a command signal from the control box 62, and after passing through the decoder, switches to the forward / reverse / stop pattern circuit according to the movement signal Sm or the static elimination signal Se. An operation signal is output. The switch operation signal is mainly applied to the high-voltage 4-wire SW circuits 66, 67, 68. The high-voltage 4-wire SW circuits 66, 67, 68 are output from the + high-voltage generation circuit and the −high-voltage generation circuit based on the switch operation signal. The high voltage is switched to generate the movement signal Sm or the static elimination signal Se.
For example, when the moving speed of the moving element 2 is slowed down, the switch speed is slowed down and a moving signal Sm having a low frequency is generated, and when the static elimination signal Sef having a voltage positive / negative time decrease in a form in which the frequency gradually increases is output, The static elimination signal Sef having a form in which the speed gradually increases and the frequency gradually increases is generated.

  In this embodiment, since the movement signal Sm is a four-phase signal shown in FIG. 3, the main body 61 has four phases of movement signal Sm1, movement signal Sm2, movement signal Sm3, and movement signal Sm4 as movement signal Sm. Output a signal. Each of the movement signal Sm1, the movement signal Sm2, the movement signal Sm3, and the movement signal Sm4 is output from each of the three high-voltage four-line SW circuits 66, 67, and 68 that are independent of each other. That is, the high-voltage 4-wire SW circuit 66, the high-voltage 4-wire SW circuit 67, and the high-voltage 4-wire SW circuit 68 are independent of each other, and each has a movement signal Sm1, a movement signal Sm2, a movement signal Sm3, and a movement signal. A movement signal Sm composed of Sm4 is generated and output. For this reason, each of the high-voltage 4-wire SW circuit 66, the high-voltage 4-wire SW circuit 67, and the high-voltage 4-wire SW circuit 68 is such that each movement signal Sm is different from each other and is synchronized with each other, for example, by a quarter cycle. It can be generated and output as a signal out of phase.

  As described above, the power supply unit 6 has a configuration including three independent high-voltage four-wire SW circuits 66, 67, and 68, but is controlled by one CPU, and the three systems are controlled based on a command signal. The independent high-voltage 4-wire SW circuits 66, 67 and 68 operate in cooperation with each other. In the power supply unit 6 having the configuration illustrated in the block diagram of FIG. 6, the high-voltage four-wire SW circuit 66 includes the movement signals Sm1, Sm2, Sm3, and the four-phase movement signals Sm for Y driving that move in the Y direction in the region Y. Sm4 is output. Similarly, the high-voltage four-wire SW circuit 67 outputs movement signals Sm1, Sm2, Sm3, and Sm4 as four-phase movement signals Sm for X drive A that are moved in the X direction in the region A. Similarly, the high-voltage four-wire SW circuit 67 outputs movement signals Sm1, Sm2, Sm3, and Sm4 as four-phase movement signals Sm for X drive B that are moved in the X direction in the region B.

  The four-phase movement signal Sm for Y driving is supplied to the plurality of electrodes 3 in the region Y of the stator 1 of FIG. 7, and the four-phase movement signal Sm for X driving A is supplied to the stator of FIG. The four-phase movement signals Sm for the X drive B are supplied to the plurality of electrodes 3 in the A region of the stator 1 in FIG.

Next, when removing electricity, the power supply unit 6 supplies the same electricity removal signal Se to all of the plurality of electrodes 3 of the stator 1. This static elimination signal Se is the static elimination signal Sef in which the voltage positive / negative time illustrated in FIG. 4 decreases, or the static elimination signal Sev in which the voltage exemplified in FIG. 5 attenuates. For example, when the power supply unit 6 adopts a static elimination signal Sef in which the voltage positive / negative time decreases as the static elimination signal Se, when the static elimination command signal is input from the control box 62, the main body 61 receives the high voltage 4-wire SW circuit. 66, the high-voltage four-wire SW circuit 67, and the high-voltage four-wire SW circuit 68 all output the same static elimination signal Sef. The static elimination signal Sef in which the voltage positive / negative time decreases is
When the moving speed is increased, the CPU outputs a command signal for increasing the frequency, and when the moving speed is decreased, the CPU outputs a command signal for decreasing the frequency. The command signal is made to be gradually earlier, and the command signal is made to be the same signal with the same phase, without changing the output of the four lines to the four-phase signals different from each other like the movement signal Sm.
Further, in the case of the power supply unit 6 adopting the static elimination signal Sev whose voltage is attenuated as the static elimination signal Se, the CPU outputs a command signal for gradually lowering the voltage instead of the command signal for increasing the frequency.

As described above, the static elimination signal Se for reducing the charge is added with a static elimination command switch in the control box 62 of the power source 6 that supplies the movement signal Sm when the static elimination is performed manually without performing automatic processing. However, it can be realized only by changing the contents of data processing executed by the CPU by software and changing the operation of the power supply 6 without increasing the size of the apparatus.
The supply of the static elimination signal Se is to change the data processing contents executed by the CPU in software without using or in combination with a forced command signal from the control box 62 operated by the operator. Thus, the CPU may be automatically processed by outputting a command that can be automatically supplied when the movement of the moving element 2 is stopped.

DESCRIPTION OF SYMBOLS 1 Stator 2 Mover 3, 3a-3d Electrode 4, 4a-4d Bus line 5, 5a-5d Input terminal 6 Power supply part 61 Main body 62 Control box 63 AC adapter or battery 64 Automatic switching circuit / voltage conversion circuit 65 I / F (interface)
66 High-voltage 4-wire SW circuit (for area Y)
67 High-voltage 4-wire SW circuit (for drive A)
68 High-voltage 4-wire SW circuit (for drive B)
100 Electrostatic actuator 200 Conventional electrostatic actuator A Region A
B area B
Sm, Sm1 to Sm4 Movement signal Se static elimination signal Sef static elimination signal (voltage positive / negative time decreases)
Sev Static elimination signal (Voltage is attenuated)
Y area Y

Claims (3)

The stator includes a stator and a mover disposed on the stator, and the stator is provided with a movement signal for moving the mover in a direction parallel to the opposing surfaces of the stator and the mover. A method of controlling an electrostatic actuator that supplies a plurality of electrodes,
Control of an electrostatic actuator that supplies an AC static elimination signal that reduces the amount of charge generated in the stator and the moving element to each of the plurality of electrodes when the movement signal is not supplied to the plurality of electrodes. Method.   2. The electrostatic actuator control method according to claim 1, wherein the static elimination signal is a signal in which a voltage positive / negative time, which is a time for applying a positive voltage and a time for applying a negative voltage, decreases with time.   The static elimination signal according to claim 1, wherein the static elimination signal is a signal in which a maximum value of an absolute value of a voltage in a voltage positive / negative time which is a time for applying a positive voltage and a time for applying a negative voltage is attenuated with time. Electric actuator control method.

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