JPH0693212B2 - Actuator driving method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving an actuator, and more particularly to a method for driving an actuator which effectively utilizes the displacement force of a piezoelectric element to move or drive an object.

[0002]

2. Description of the Related Art Conventionally, moving means utilizing fluid pressure such as hydraulic pressure and pneumatic pressure have been widely used for transporting objects in various machines. This type of moving means is indispensable to the transport system in order to generate a relatively large force and stroke. On the other hand, conventionally, this type of moving means has a problem that it is difficult to perform highly accurate control because it uses a fluid. However, in recent years, a piezoelectric element (piezo) has been receiving attention. In other words, the displacement force of the piezoelectric element is obtained by causing distortion when an electric field is applied to a certain kind of crystal body or sintered body. Therefore, if an object is moved or driven by using this displacement force, the mechanical Since electrical control is performed rather than physical control, positioning and the like can be performed reliably and accurately.

[0003]

Therefore, the present invention has been made by paying attention to the remarkable performance improvement of a piezoelectric element in recent years, such as the invention of a composite piezoelectric ceramic, and effectively uses the displacement force of the piezoelectric element. It is an object of the present invention to provide a novel actuator driving method for moving or driving an object two-dimensionally .

[0004]

Means for Solving the Problems] To achieve the above object, the present invention, an actuator, a first piezoelectric element unit consisting of the group, and a second piezoelectric element unit consisting of the group to each other Drive by arranging so as to be orthogonal
In the method, each of the piezoelectric element unit constituting the first piezoelectric element unit group includes a first piezoelectric element stack stacked in a first direction, laminated to a second direction crossing the first direction And a second piezoelectric element laminated body,
Each of the piezoelectric element units forming the second piezoelectric element unit group includes a third piezoelectric element laminated body laminated in a direction intersecting the first and second directions, and a third piezoelectric element laminated body along the second direction. A fourth piezoelectric element laminated body, and a second piezoelectric element laminated body side of the first piezoelectric element unit and a second piezoelectric element laminated body side of the first piezoelectric element laminated body.
The third piezoelectric element laminated body side of the piezoelectric element unit is attached to the movable member, the second piezoelectric element laminated body side and the fourth piezoelectric element laminated body face the base side, and at least the second piezoelectric element laminated body. The movable member is fixed to the base by applying a voltage to the base, and then the movable member is moved in the first direction by applying a voltage to the first piezoelectric element laminate. Further, by stopping the application of the voltage to the second piezoelectric element laminate, and then applying the voltage to the fourth piezoelectric element laminate, the movable member is fixed to the base, and the third member is further provided. By applying a voltage to the piezoelectric element laminate, the moved member is moved in the second direction, and further, the voltage application to the fourth piezoelectric element laminate is stopped, and these are repeated. , The first and 3, characterized in that for moving the to be moving member fixed to the piezoelectric element laminated body side to the first and second intersecting directions.

[0005]

In the method of the present invention , the first piezoelectric element unit
The second piezoelectric element laminate is once fixed to the base by applying a voltage to the two piezoelectric element laminate , and then the first piezoelectric element
When a voltage is applied to the laminated body , the first piezoelectric element laminated body expands and the movable member is displaced in the first direction. Second piezoelectric element
Similarly, the voltage is applied to the child unit and stopped. By repeating the application of the voltage and the stop thereof in this manner, the member to be moved can be synchronously moved in two directions .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the actuator driving method according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a first embodiment to which the actuator driving method according to the present invention is applied.

As shown in the drawing, a plurality of bent rod-shaped piezoelectric element units 12 that are displaced by a piezoelectric element unit described later are planted in a matrix on the surface of the movable member 10. In this embodiment, the piezoelectric element unit is used.
Knit 12 has its moving direction as in the odd and even rows counted in the direction of the arrow in the figure, just provided to move operate differently an X-Y-direction. In this case, the piezoelectric
As shown in FIG. 2, the element unit 12 is formed into a round bar shape and bends along the way, that is, a pair of vertical portions 14 and 20 are formed with the horizontal portion 18 interposed therebetween, and one vertical portion 14 is further formed. Is the moving part
The material is fixed to a mounting hole 16 formed on one surface of the material 10 by press fitting or the like. Further, the horizontal portion 18 and the other vertical portion 20 of the piezoelectric element unit 12 include first and second piezoelectric element laminated bodies 22a and 22b, respectively, in a part thereof.

The first and second piezoelectric element laminates 22a and 22b are formed by laminating a large number of disc-shaped piezoelectric ceramics into a round bar shape having a predetermined length, and power supply lines 24a and 24b.
Connected to the DC power supplies not shown in the figure respectively. In this embodiment, the power supply line 24 from each piezoelectric element unit 12 is
a and 24b is converged to a control circuit, not shown, each of the piezoelectric
The element unit 12 is configured to perform a displacement operation in conjunction with a signal from the control circuit. Further, the first and second piezoelectric element laminates 22a and 22b are expanded and displaced in the axial direction of the piezoelectric element unit 12 when a voltage having a predetermined polarity is applied via the power supply lines 24a and 24b, respectively. It can be easily understood that it is a thing.

The actuator for carrying out the method according to the present invention is basically constructed as described above. Next, its operation and effect will be explained.

Now, the piezoelectric element implanted in the movable member 10
For each of the displacement member groups that are displaced in the X direction and the Y direction in the unit 12, if the displacement operation having the four operations shown in FIG. 3 as one cycle is alternately performed by a signal from a control circuit (not shown),
As shown in FIG. 4, the moved member 10 freely moves in the XY directions with respect to the base 26.

This will be described in more detail with reference to FIGS. 3A to 3D. First, each piezoelectric element unit 1 will be described.
Second piezoelectric element laminate 2 provided in the vertical portion 20 in FIG.
A predetermined voltage is applied to 2b via the power supply line 24b. Accordingly, the second piezoelectric element stack of the vertical portion 20 is formed.
The body 22b is expanded and displaced, and the tip end surface 20a of the vertical portion 20 abuts against the base 26 as shown in FIG. At this time, the piezoelectric element unit of the other group
In the case 12, since no voltage is applied to the second piezoelectric element laminate 22b, the vertical portion 20 does not extend and displace,
Therefore, the piezoelectric element unit 12 of the other group is the base 2
It is a little floating from 6.

Next, in the state described above, a predetermined voltage is applied to the first piezoelectric element laminate 22a in the horizontal portion 18 this time through the power supply line 24a. Thereby, the horizontal portion 1
The first piezoelectric element laminate 22a of No. 8 is expanded and displaced in the horizontal direction as in the state of FIG. 3B. At this time, the tip end surface 20a of the vertical portion 20 is strongly pressed against the base 26 and remains fixed due to the frictional resistance between the tip end surface 20a and the base 26. The movable member 10 horizontally moves in the direction of the arrow in the figure.

Thereafter, the second piezoelectric element of the vertical portion 20 is formed.
The voltage application to the laminated body 22b is stopped, and the piezoelectric element laminated body 22b is contracted and displaced. At this time, in each piezoelectric element unit 12 of the other group , the second piezoelectric element stack is used.
When a voltage is applied to the body 22b, the piezoelectric element laminate 22b
Is stretched and displaced. Thus, now become the moving member 10 is therefore supported by the piezo stack of the other group, one of the piezoelectric element unit 12 is slightly floated from the base 26 (FIG. 3 (c) See state).

Finally, the voltage application to the first piezoelectric element laminate 22a in the horizontal portion 18 is stopped. As a result, the piezoelectric element laminate 22a contracts and displaces, and eventually one piezoelectric element unit 12 returns to the state of FIG. 2 (see the state of FIG. 3D). Of course, after this, the other pressure
The application of the voltage to the second piezoelectric element laminate 22b of the electric element unit 12 is also stopped, and the movable member 10 moves to both piezoelectric elements.
It is supported by the element unit .

In this way, one piezoelectric element unit 1
Vertical displacement 2 of the second piezoelectric element stack 22b (elongated displacement) → horizontal displacement (elongation displacement) in the first piezoelectric element stack 22a → vertical displacement of the second piezoelectric element stack 22b (contraction displacement) → First piezoelectric element laminate 2
If the horizontal displacement (contraction displacement) in 2a is repeatedly displaced as one cycle, the movable member 10 sequentially moves in the X direction or the Y direction. In other words, each of the piezoelectric elements
Unit 12 is a so-called displaced operates as Inchworm be
The moving member 10 is linearly moved by a predetermined stroke. Therefore, if the displacement movement of the piezoelectric element unit to displace the piezoelectric element unit and a Y direction displacement in the X direction alternately, the moving member 10, as shown in FIG. 4, freely moving an X-Y-direction .

On the other hand, when the movement opposite to the movement illustrated in FIG. 4 is to be performed, each piezoelectric element unit 12 is moved.
The horizontal displacement (extension displacement) of the first piezoelectric element laminate 22a → the vertical displacement (extension displacement) of the second piezoelectric element laminate 22b → the horizontal displacement (contraction displacement) of the first piezoelectric element laminate 22a → the 2 Piezoelectric element stack 22b
It will be easily understood that the vertical displacement (contraction displacement) in (1) should be repeated for one cycle.

Next, FIGS. 5 to 8 show second to fifth embodiments to which the actuator driving method according to the present invention is applied.

FIG. 5 shows an embodiment in which an elastic body 30 made of rubber or the like is arranged on the tip surface 20a of the vertical portion 20 of the actuator shown in FIG. In this case, the elastic body 30 increases the frictional resistance at the time of crimping with the base 26 and the like, and the movement control is reliably achieved.

In FIG. 6, the movable member 10 shown in FIG. 4 is formed into a curved surface, and the base 26, which is also formed into a curved surface, is X-shaped.
An example will be shown in which the Y-direction is freely moved.

FIG. 7 shows a piezoelectric element in which the movable member 10 shown in FIG. 4 is formed in a cylindrical shape, is fixed, and a shaft 32 having a circular cross section is fitted therein, and is displaced in the XY direction. An embodiment is shown in which the shaft 32 is moved or rotated in the axial direction by the unit 12.

FIG. 8 shows an embodiment in which the movable members 10 shown in FIG. 7 are combined in multiple stages to form a tubular member which is rotatable and expandable / contractible as a whole.

[0023]

As described above, according to the present invention,
By driving the two piezoelectric element unit portions having different arrangement directions, it is possible to obtain an effect that an object fixed to the piezoelectric element unit can be easily moved in an arbitrary direction. In this case, since the displacement control is performed electrically, it is possible to obtain an effect that the displacement control is performed with extremely high accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment to which an actuator driving method according to the present invention is applied.

FIG. 2 is an enlarged cross-sectional view of a main part of the device shown in FIG.

FIG. 3 is a cross-sectional view showing an operation sequence of displacement members of the apparatus of FIG.

FIG. 4 is an explanatory view showing a working state of the apparatus of FIG.

FIG. 5 is a sectional view showing a second embodiment to which the actuator driving method according to the present invention is applied.

FIG. 6 is a front view showing a third embodiment to which the actuator driving method according to the present invention is applied.

FIG. 7 is a perspective view showing a fourth embodiment to which the actuator driving method according to the present invention is applied.

FIG. 8 is a front view showing a fifth embodiment to which the actuator driving method according to the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... To-be-moved body 12 ... Piezoelectric element unit 14 ... Vertical part 16 ... Mounting hole 18 ... Horizontal part 20 ... Vertical part 22a, 22b ... Piezoelectric element laminated body 24a, 24b ... Power supply line 26 ... Base 30 ... Elastic body 32 ... shaft

Claims (1)

[Claims] 1. A method of arranging and driving a first piezoelectric element unit consisting of a group and a second piezoelectric element unit consisting of a group that constitute an actuator so as to be orthogonal to each other.
In each of the piezoelectric element unit constituting the first piezoelectric element unit group is laminated with the first piezoelectric element stack stacked in a first direction, the second direction crossing the first direction and second and a piezoelectric element stack, each of the piezoelectric element unit constituting the second piezoelectric element unit group, the third piezoelectric said first and stacked in a direction crossing the second direction An element laminated body and a fourth piezoelectric element laminated body laminated along the second direction, wherein the first piezoelectric element laminated body side of the first piezoelectric element unit and the third piezoelectric element unit third portion The piezoelectric element stack side is attached to the movable member, the second piezoelectric element stack side and the fourth piezoelectric element stack side face the base side, and a voltage is applied to at least the second piezoelectric element stack. The movable member is fixed to the base by Then, by applying a voltage to the first piezoelectric element laminate, the movable member is moved in the first direction, and the application of voltage to the second piezoelectric element laminate is stopped, By applying a voltage to the piezoelectric element laminated body of No. 4, the movable member is fixed to the base, and by applying a voltage to the third piezoelectric element laminated body, the movable member is moved to the second movable member. In the direction, and the application of voltage to the fourth piezoelectric element laminate is stopped, and these operations are repeated to move the member to be moved fixed to the first and third piezoelectric element laminates. A method of driving an actuator, characterized in that the actuators are moved in first and second directions intersecting with each other.