JPH11346489A - Piezoelectric actuator, control method thereof, and computer-readable memory with program for executing control method of piezoelectric actuator by computer stored therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a piezoelectric actuator performing rotation control effectively. SOLUTION: A drive control section 4 comprises a voltage drive means, i.e., a power supply section generating a voltage, for applying a drive voltage of specified frequency to a piezoelectric element 23 in an oscillator block 2, and a drive control circuit for modulating that voltage to an arbitrary AC voltage. A plurality of piezoelectric elements 23 are applied with AC voltages, respectively. The AC voltages can be applied to respective piezoelectric elements 23, while varying the phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric actuator capable of performing effective rotation control, a method of controlling the piezoelectric actuator, and a computer-readable storage medium storing a program for causing a computer to execute the method of controlling the piezoelectric actuator. .

[0002]

2. Description of the Related Art At present, OA equipment and information processing equipment have been miniaturized, and accordingly, piezoelectric actuators have attracted attention as a power source used for driving and transporting. As an example of such a piezoelectric actuator, a micro piezoelectric motor developed by the present applicant is known (IEEJ).
15th Sensor Symposium TECHNICAL DIGEST1
81-184, 1997).

FIG. 10 shows an assembly diagram of the micro piezoelectric motor. The micro piezoelectric motor 500 includes a disk-shaped rotary moving body 1 having a shaft projection 11 and a vibrating body block 5.
02 and a base chassis 3 that supports the shaft projection 1. The vibrating body block 502 is provided with three bending displacement mechanism portions 522 in which the piezoelectric elements 4 that generate expansion and contraction motion are attached to the beam portions 521. The bending displacement mechanism 52
2 has an L-shape, and the short side end of the L-shape is fixed to the center 523 of the vibrator block 502.
The bending displacement mechanism 522 is provided on the sliding portion 1 of the rotary moving body 1.
2 are arranged so as to coincide with the tangential direction of the circle included therein.

[0004] Further, the rotary moving body 1 and the base chassis 3
The rotary moving body 1 and the vibrating body block 502 are brought into contact with each other under a constant pressure by using a magnet material generating a magnetic attraction force. Further, a non-magnetic material is used for the vibrating body block 502, particularly, the bending displacement mechanism 522 so as not to be affected by the magnetic force of the magnet material. Shaft projection 11 of rotary moving body 1
Is supported by a hollow shaft hole 525 of the vibrating body block 502. The main body of the rotary moving body 1 is formed of a metal or a resin, and the sliding surface 12 with the vibrating body block 502 is subjected to an oxide film treatment. In addition, the rotary moving body 1 and the vibrating body block 50
Photofabrication technology such as etching is used for the formation of 2 and the like.

FIG. 11 is an explanatory diagram showing the operation principle of this micro piezoelectric motor. By applying a drive voltage of a specific frequency to the piezoelectric element 4, the piezoelectric element 4 expands and contracts in the direction of arrow A in the figure. Due to this expansion and contraction, the bending displacement mechanism 5
22 vibrates in the direction of arrow B in the figure. Bending displacement mechanism 52
When 2 vibrates, the tip of the bending displacement mechanism section 522 comes into contact with the rotary moving body 1. Since the contact direction is not perpendicular to the rotary moving body 1 but the direction indicated by the arrow C in the figure,
The rotational moving body 1 is moved by the lateral force component Ch.

[0006]

In the conventional micro piezoelectric motor 500, a plurality of piezoelectric elements are used, and the rotary moving body is rotated by applying a driving voltage to each of these piezoelectric elements. That is, each piezoelectric element 2
As shown in FIG. 11, each of the members 3 contacts the rotary moving body 1 and rotates the rotary moving body 1 by the lateral force component Ch. Here, when rotating the rotating body 1 by a plurality of bending displacement mechanisms 522, the ability of the rotating body 1 changes depending on how each of the bending displacement mechanisms 522 is vibrated. Further, depending on the product to which the micro piezoelectric motor 500 is applied, a case where importance is attached to speed or a case where importance is attached to torque is assumed.

[0007] The present invention has been made in view of the above, and an object of the present invention is to provide a piezoelectric actuator capable of performing effective rotation control and a method of controlling the piezoelectric actuator.

[0008]

In order to achieve the above-mentioned object, a piezoelectric actuator according to the present invention comprises a rotating body and one end fixed at the other end extending in the tangential direction of an inner circle of the rotating body. A vibrating body comprising a plurality of beam portions and a plurality of piezoelectric bodies spread for each of the beam portions, and a power supply for applying a voltage by giving a phase difference between the plurality of piezoelectric bodies.

A voltage applied between a plurality of piezoelectric bodies has a phase difference. By providing a phase difference, each of the plurality of beam portions comes into contact with the rotary moving body with a time interval. For this reason, the amount of movement due to the lateral force component Ch (see FIG. 11) increases, so that the rotating moving body can be rotated at high speed.

Further, in the piezoelectric actuator according to the present invention, in the above-mentioned piezoelectric actuator, the value of the phase difference is a reciprocal of twice the number of the beam portions.

As described above, by setting the value of the phase difference between the piezoelectric bodies to be the reciprocal of the number obtained by doubling the number of the beam portions, the plurality of beam portions come into contact with the rotary moving body at equal time intervals. Therefore, high-speed and smooth rotation is possible.

Further, the piezoelectric actuator according to the present invention has a rotary moving body, a plurality of beam portions extending in an inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end, and is extended for each of the beam portions. And a power supply for applying a voltage of the same phase between the plurality of piezoelectric bodies.

By applying the same phase voltage between the plurality of piezoelectric bodies, the plurality of beam portions come into contact with the rotary moving body substantially simultaneously. Therefore, a large torque can be obtained with a small amount of movement.

Further, the piezoelectric actuator according to the present invention has a rotary moving body, a plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end, and is mounted on each of the beam portions. A vibrating body comprising a plurality of piezoelectric bodies, a power supply for applying a voltage to each of the plurality of piezoelectric bodies, and a phase of the voltage between the piezoelectric bodies upon applying a voltage from the power supply to each of the plurality of piezoelectric bodies. And phase control means for performing control.

By performing the phase control, the rotary moving body can be rotated effectively. For example, a high torque can be obtained by applying a voltage having the same phase to each piezoelectric body at the time of the start of rotation, and a high-speed rotation with little energy loss can be performed by applying a voltage having a phase difference during the rotation.

In the piezoelectric actuator according to the present invention, in the piezoelectric actuator, when the phase control means applies a voltage to each of the plurality of piezoelectric bodies, the phase control means applies a phase difference to the voltage between the piezoelectric bodies. It has a switching means for switching between the case of applying the same phase voltage and the case of applying the same phase voltage.

For example, when a voltage having the same phase is applied to each piezoelectric body, a high torque can be obtained, and when a voltage having a phase difference is applied, rotation can be performed at high speed with little energy loss. By performing such switching, the rotating moving body can be effectively rotated.

Further, the piezoelectric actuator according to the present invention has a rotary moving body, a plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end, and is mounted on each of the beam portions. A vibrating body comprising a plurality of piezoelectric bodies, a power supply for applying a voltage to each of the plurality of piezoelectric bodies, and voltage control means for controlling a voltage applied from the power supply to each of the plurality of piezoelectric bodies. It is.

For example, when a high voltage is applied to the piezoelectric body, the expansion and contraction of the piezoelectric body increases, and the deflection of the beam portion also increases accordingly. Therefore, a large torque can be obtained. The lower the applied voltage, the lower the torque but the lower the energy consumption. By controlling the voltage in this way, the rotating moving body can be effectively rotated.

Further, the method of controlling a piezoelectric actuator according to the present invention is characterized in that a plurality of beam portions extending in the inner circle tangent direction of the rotary moving body and fixed at one end and free at the other end and a plurality of piezoelectric members spread on the beam portions are provided. When a vibrating body is formed from the body, a voltage is applied to the piezoelectric body to vibrate the beam, and the beam is brought into contact with the rotating body to rotate the rotating body. A voltage having the same phase is applied between the plurality of piezoelectric bodies, and during normal rotation, control is performed so as to give a phase difference to the voltage applied between the plurality of piezoelectric bodies.

When a voltage having the same phase is applied to each piezoelectric body, a high torque can be obtained, and when a voltage having a phase difference is applied, rotation can be performed at high speed with little energy loss. By performing such control, the rotating moving body can be effectively rotated.

Further, the method of controlling a piezoelectric actuator according to the present invention is characterized in that a plurality of beam portions extending in the inner circle tangential direction of the rotary moving member and having one end fixed and the other end free, and a plurality of piezoelectric members spread on the beam portion are provided. When a vibrating body is formed from the body, a voltage is applied to the piezoelectric body to vibrate the beam, and the beam is brought into contact with the rotating body to rotate the rotating body. A high voltage is applied to the plurality of piezoelectric bodies, and control is performed such that a low voltage is applied to the plurality of piezoelectric bodies during normal rotation.

When a high voltage is applied, the amplitude of the beam increases, and the torque increases. Further, by applying a low voltage, energy consumption can be reduced. By performing such control, the rotating moving body can be effectively rotated.

A computer-readable storage medium according to the present invention stores a program for causing a computer to execute the above-described method of controlling a piezoelectric actuator.

In some cases, the piezoelectric actuator is controlled by using a computer. At this time, a high torque can be obtained by controlling the piezoelectric actuator using a storage medium storing a program for controlling the piezoelectric actuator and computer hardware. It is possible to perform high-speed rotation with little energy loss. Therefore, the rotary moving body can be rotated effectively.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. The present invention is not limited by the embodiment.

(Embodiment 1) FIG. 1 is an assembly diagram showing a micro piezoelectric motor according to Embodiment 1 of the present invention. The micro piezoelectric motor 100 includes a rotating body 1 having a shaft projection 11, a vibrating body block 2 having an L-shaped bending displacement mechanism 21, and a base chassis 3 supporting the shaft projection 11. ing. In addition, the rotary moving body 1
The rotating chassis 1 and the vibrating body block 2 are brought into contact with each other under a constant pressure by using a magnet material generating a magnetic attraction force for the base chassis 3. For example, a stainless steel-based magnet material is used for the rotating body 1 and a neodymium-based magnet material is used for the base chassis. Since the base chassis 3 is attracted to the rotating body side by the magnet material, the sliding portion 12 of the rotating body 1
Stable adhesion between the actuator and the bending displacement mechanism 21 of the vibrating body block 2 can be obtained. Further, it is preferable to use a non-magnetic material for the vibrating body block 2, especially for the bending displacement mechanism 21, so as not to be affected by the magnetic force of the magnet material.

The shaft projection 11 of the rotary moving body 1 is supported by a hollow shaft hole 22 of the vibrating block 2. Conversely, a hollow shaft hole may be provided on the rotating body side, and a shaft projection may be provided on the vibrating body block side. Sliding part 12 of rotary moving body 1
Has a large friction coefficient and excellent abrasion resistance because it is a portion where friction with the bending displacement mechanism 22 occurs.
It is preferable to use a material that satisfies requirements such as maintaining a stable coefficient of friction. For example, the main body of the rotary moving body 1 is formed of a metal or resin system, and the sliding portion 12 is subjected to an oxide film treatment. Also, the sliding portion 12 is
It may be formed using a cellulosic fiber, a carbon fiber, a composite material of whisker and phenol resin, or a composite material of polyimide resin and polyamide resin. The drive control unit 4 is a voltage drive unit for applying a drive voltage having a specific frequency to the piezoelectric element 23 of the vibrating body block 2.
It is composed of a power supply unit for generating a voltage and a drive control circuit for modulating the voltage into an arbitrary alternating current. In the figure, an AC voltage can be applied to each of the three piezoelectric elements 23. At this time, an AC voltage can be applied to each of the piezoelectric elements 23 by changing the phase.

FIG. 2 shows a detailed structure of the vibrating body block 2. The bending displacement mechanism 21 has a structure in which three piezoelectric elements 23, each of which is equally arranged, and each of which generates a stretching motion, are attached to the beam 24. The bending displacement mechanism 21 has an L-shape, and the short side end of the L-shape is
Is fixed to the center part 25 of This bending displacement mechanism 2
1 is arranged so as to coincide with the tangential direction of a circle included in the sliding portion 12. The direction of rotation of the rotary moving body 1 is determined by the direction of the elliptical motion drawn by the free end of the bending displacement mechanism 21. Here, since the rotary moving body 1 is pivotally supported, if the motion trajectory of the bending displacement mechanism 21 is made to coincide with the motion trajectory of the rotary moving body 1, the rotation moving body 1 Movement conversion becomes efficient.

In the figure, the bending displacement mechanism 21 projects clockwise, but if the projecting direction is reversed, the rotary moving body 1 will rotate in the opposite direction. Further, the rotation torque and the rotation speed of the micro piezoelectric motor 100 are determined by the distance from the rotation center of the bending displacement mechanism 21 and the shape and number of the bending displacement mechanism 21 provided in the vibrating body block 2. The position of the bending displacement mechanism 21, that is, the distance from the rotation center of the rotary moving body 1 to the bending displacement mechanism 21 and the shape and number of the bending displacement mechanism 21 are set based on the required specifications of the micro piezoelectric motor 100. I do.

The piezoelectric element 23 is a material having a function of generating distortion, a function of resonance, and a function of generating voltage. That is, a stress or displacement occurs according to the applied voltage,
It is a material that exhibits a characteristic that a resonance phenomenon is caused by the frequency of an applied voltage and a voltage is generated according to the applied pressure.
Examples of the piezoelectric ceramic that is a typical example of the piezoelectric element 23 include:
Barium titanate, lithium niobate, lead zirconate titanate and the like can be mentioned. Further, a functionally graded material or lithium niobate can be used instead of the piezoelectric ceramics. For the vibrating body block, a metal-based or non-metal-based elastic material such as stainless steel, beryllium copper, phosphor bronze, brass, duralumin, titanium or silicon is used.

It is preferable to use a photofabrication technique such as etching for forming the rotary moving body 1 and the vibrating body block 2. By using a non-machining process, deformation, stress, and mechanical stress generated at the time of forming can be eliminated. In addition, by increasing the precision of the parts, the assembling adjustment process of each element part can be minimized, and the function and reproducibility are stabilized.

The beam 24 and the electrostrictive element 23 are integrated by bonding. The conditions required for such bonding are:
That is, the bonding layer is very thin, the bonding layer is very hard and tough, and the resistance value near the resonance frequency after bonding the piezoelectric element 23 and the beam portion 24 is small. For example, a polymer adhesive represented by hot melt and epoxy resin is used for the bonding. Note that the piezoelectric element 23 may be directly bonded without using an adhesive. Also, thin film formation,
The piezoelectric element 23 may be provided by a process for forming a pressure film. The bending displacement mechanism 21 includes:
There is a unimorph type composed of one piezoelectric element 23, a bimorph type composed of two piezoelectric elements, or a multimorph type composed of four or more piezoelectric elements, and any of them may be used. . The material of the piezoelectric element 23 and the beam portion 24 and the method of bonding them are the same as those of the micro piezoelectric motor 1.
It is set by the displacement amount, force, responsiveness, and structural constraints of the bending displacement mechanism 21 required at 00.

More specifically, in the vibrating body block 2 shown in FIG.
1, and the bending displacement mechanism portions 21 are evenly arranged along the outer periphery of the vibrating body block 2. The diameter is on the order of a few millimeters. The beam portion 24 of the bending displacement mechanism 21 is formed by etching a copper-based material of about 100 microns. The piezoelectric element 23 is made of thin film lead zircon titanate having a high piezoelectric constant. There is a bonding interface between the beam portion 24 and the piezoelectric element 23 even if it is a direct bonding or a bonding using an adhesive. This bonding interface is an important factor that determines the propagation characteristics between the beam 24 and the piezoelectric element 23. For this reason, the properties of the adhesive and its thickness control are important.
In this example, an epoxy-based adhesive was used to obtain an optimum film thickness.

Next, the shape of the bending displacement mechanism 21 is set in consideration of the fact that its effective length, especially the length from the fixed end to the free end, has a correlation with the displacement of the longitudinal motion and the elliptical motion. . Further, since the natural frequency of each bending displacement mechanism 21 depends on the shape, it is determined from the results of the simulation model and the experimental data so as to meet the specifications. The shape of the vibrating body block 2 of the present embodiment is
0 and the load condition of the rotary moving body 1.

The bending displacement mechanism 21 has a unimorph structure. This is because it has characteristics that it is difficult to have hysteresis on the displacement voltage characteristics. In addition, the displacement amount is small as compared with the bimorph type, but the generated force is large, and the applied load and the pressing force of the rotary moving body 1 are appropriate. Note that, depending on the specifications of the rotary actuator 100, the displacement and the force can be increased by adopting a multi-morph type, keeping the thickness constant, and increasing the number of layers. In addition, a taper can be provided from the fixed end to the free end of the bending displacement mechanism 21 to improve responsiveness. According to the vibrating body block 2 having such a configuration, the bending displacement of the bending displacement mechanism 21 can be excited very stably. The bending displacement mechanism 21 of the vibrating body block 2
Are not limited to the example shown in FIG.

(Embodiment 2) Embodiment 2 of the present invention
The micro piezoelectric motor according to the first embodiment is structurally the same as the micro piezoelectric motor 100 according to the first embodiment, but is adapted to control the phase difference of an AC voltage applied between the piezoelectric elements 23 and apply the AC voltage. FIG. 3 is a block diagram showing a phase control unit of the micro piezoelectric motor 100. The signal generator 101 determines the frequency of the voltage applied to the piezoelectric element 23. The signal generator 101 is connected to the phase controller 102. In the phase control unit 102, each piezoelectric element 23
A voltage having a phase difference between them is applied. The phase difference is a reciprocal (1 / 2x) of a value (2x) obtained by doubling the number (x) of the bending displacement mechanism 21 in the signal period. In this case,
Since there are three bending displacement mechanisms 21, the given phase difference is 1/6. The voltage phase-controlled by the phase control unit 102 is amplified by the driver 103 and sent to each piezoelectric element 23. FIG. 4 shows a timing chart of the phase control. With respect to the period of the piezoelectric element 23a,
The cycle of b is shifted by 1/6. Also, the period of the piezoelectric element 23c is shifted by 1/6 from the period of the piezoelectric element 23b. By applying a voltage to each of the piezoelectric elements 23 with the phases shifted evenly in this manner, the bending displacement mechanism 21 comes into contact with the rotary moving body 1 at equal time intervals. The operating principle of the bending displacement mechanism 21 is as shown in the conventional example (see FIG. 11). In this way, if a voltage is applied by giving a phase difference between the piezoelectric elements 23, the bending displacement mechanism 21 continuously contacts the rotating body 1 at equal time intervals. The rotation speed increases.

In addition to the case where the number of the bending displacement mechanism portions 21 is three as in the present embodiment, even when the number of the bending displacement mechanism portions 21 is three or more or two, a voltage having a phase difference between the piezoelectric elements 23 is applied. The application can increase the high rotation speed. Bending displacement mechanism 2
Regardless of the number of 1s, the phase difference to be given is the reciprocal (1 / 2x) of the value (2x) obtained by doubling the number (x) of the bending displacement mechanism 21 in the signal period. Note that the phase difference may be arbitrarily defined regardless of the general formula. For example, the phase difference is determined by the number (x) of the bending displacement mechanisms 21 in the signal period.
It may be a reciprocal multiple of (1 / x). Alternatively, a voltage having the same phase may be applied to the two bending displacement mechanisms 21 and a phase difference may be applied to the voltages applied to the remaining bending displacement mechanisms 21. These phase controls are performed by the phase control unit 102 according to an arbitrary setting.

It is also possible to control so that the same phase voltage is applied to the piezoelectric element 23. As shown in FIG. 5, by applying a voltage having the same phase to each piezoelectric element 23, the bending displacement mechanism section 21 comes into contact with the rotating body 1 substantially simultaneously.
For this reason, although the rotation speed decreases, the torque can be increased. In the phase control unit 102, each piezoelectric element 23
Switching control is performed between the case where a voltage with a phase shifted therebetween is applied and the case where a voltage with the same phase is applied. For example, at the start of rotation, a voltage of the same phase is applied between the piezoelectric elements 23 to obtain a quick rise, and during rotation, a voltage of a different phase is applied between the piezoelectric elements 23 to obtain a fast rotation. I do. The phase control unit 102 includes, for example, a general computer (not shown) and a storage medium (not shown) storing a program for causing the computer to execute the switching control.

(Embodiment 3) Embodiment 3 of the present invention
Is structurally the same as the micro piezoelectric motor 100 of the first embodiment, but does not apply a phase difference to the voltage applied between the piezoelectric elements 23 but controls the voltage itself. It was made. FIG.
FIG. 10 is a block diagram illustrating a voltage control unit of a micro piezoelectric motor according to Embodiment 2 of the present invention. Signal generator 101
Determines the frequency of the voltage applied to the piezoelectric element 23.
The signal generator 101 is connected to the voltage controller 104. The voltage control unit 104 controls a voltage value applied between the piezoelectric elements. As shown in FIG. 7A, the voltage control unit 104 increases the voltage value applied to the piezoelectric element 23 during the rotation rising period. As the voltage applied to the piezoelectric element 23 increases, the displacement of the piezoelectric element 23 increases accordingly. For this reason, the bending displacement mechanism 21 vibrates greatly,
The component of the lateral force on the rotary moving body 1 increases (see FIG. 11). For this reason, the obtained torque increases. Next, since a large torque is not required during the normal operation period, the voltage applied to the piezoelectric element 23 is reduced. FIG.
<B> shows in detail the drive waveform at the transition from the rising period to the normal operation period in FIG. Exercise is obtained. Voltage control unit 104
Is composed of, for example, a general computer (not shown) and a storage medium (not shown) storing a program for causing the computer to execute the switching control. (Fourth Embodiment) A micro piezoelectric motor according to a fourth embodiment of the present invention is a micro piezoelectric motor 1 according to the first embodiment.
Although the structure is the same as 00, the phase of the AC voltage applied between the piezoelectric elements 23 is controlled and the voltage itself can be controlled. The phase and the voltage can be controlled independently. In some cases, the control can be performed even when the voltage and the voltage are combined. FIG. 8 is a block diagram showing a voltage control unit of a micro piezoelectric motor according to Embodiment 4 of the present invention. The signal generator 101 determines the frequency of the voltage applied to the piezoelectric element 23. The signal generator 101 is connected to the phase controller 105. The phase control unit 105 generates a phase signal for applying a voltage having a phase difference between the piezoelectric elements 23. The phase control unit 105 is connected to the voltage control unit 106 and the driver unit 103, and controls the voltage value applied between the piezoelectric elements in the voltage control unit 106. The voltage control unit 106 is connected to the driver unit 103. The driver unit 103 switches the applied voltage value controlled by the voltage control unit 106 based on the phase signal generated by the phase control unit 105 by the driver unit 103, and
3 can be applied. Therefore, the supply of the driving power applied to the piezoelectric element 23 can be driven by various combinations of the phase and the voltage value. For example, when a maximum torque such as a rise of rotation is required, the voltage value applied to each piezoelectric element 23 is controlled by the voltage control unit 106 to be maximum.
In addition, if the phase control unit 105 sets the same phase control for each piezoelectric element 23, the maximum torque can be obtained. Next, during the normal operation period, a large torque is not required.
The voltage applied to the piezoelectric element 23 is reduced, and the phase control unit 10
By giving a phase difference to the voltage applied to each piezoelectric element 23 in 5, it is possible to obtain high-speed rotation and to suppress power consumption. Further, not only during the rotation rising period and the normal operation period, but also during acceleration and deceleration can be easily controlled by combining the phases and voltages applied to the respective piezoelectric elements 23. The phase control unit 102 includes, for example, a general computer (not shown) and a storage medium (not shown) storing a program for causing the computer to execute the switching control. (Fifth Embodiment) A micro piezoelectric motor according to a fifth embodiment of the present invention is similar to the micro piezoelectric motor 1 of the first embodiment.
Although the structure is the same as 00, the phase and the voltage of the AC voltage applied between the piezoelectric elements 23 are controlled based on information from the rotation sensor such as the rotation angle or the rotation speed of the rotary moving body 1. Things. FIG. 9 is a block diagram showing a voltage control unit of a micro piezoelectric motor according to Embodiment 5 of the present invention. The signal generator 101 determines the frequency of the voltage applied to the piezoelectric element 23. The signal generator 101
It is connected to the phase control unit 105. Phase control unit 105
Then, a phase signal for applying a voltage having a phase difference between the piezoelectric elements 23 is generated. Phase control unit 105
Is connected to the voltage control unit 106 and the driver unit 103, and the voltage control unit 106 controls a voltage value applied between the piezoelectric elements. The voltage control unit 106 includes the driver unit 10
3 is connected. The driver unit 103 can switch the applied voltage value controlled by the voltage control unit 106 based on the phase signal generated by the phase control unit 105 by the driver unit 103 and apply it to the piezoelectric element 23. Therefore, the configuration is such that the supply of drive power applied to the piezoelectric element 23 can be driven by various combinations of phase and voltage values. At this time, phase switching and voltage control are performed by the rotation sensor 1.
It is configured to be switched according to the rotation position or rotation speed from 07. As the rotation sensor 107, for example, a magnetic sensor such as a Hall element may be used, or a speed sensing device such as an acceleration sensor may be used. By using the rotation sensor 107 in this manner, a feedback system can be configured, servo control can be performed in a closed loop, and a more accurate rotation actuator can be configured.

[0041]

As described above, according to the piezoelectric actuator of the present invention, the rotary moving body, the plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end are provided. A vibrating body consisting of a plurality of piezoelectric bodies spread for each unit and a power supply for applying a voltage by giving a phase difference between the plurality of piezoelectric bodies are provided, so that each of the plurality of beam parts has a time interval. To contact the rotating body. Therefore, the rotary moving body can be rotated at a high speed.

Further, in the piezoelectric actuator of the present invention, the value of the phase difference is set to the reciprocal of twice the number of the beam portions, so that the plurality of beam portions come into contact with the rotary moving body at equal time intervals. Become. Therefore, high-speed and smooth rotation is possible.

In the piezoelectric actuator according to the present invention, the rotary moving body, a plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end are spread for each of the beam portions. Since a vibrating body composed of a plurality of piezoelectric bodies and a power supply for applying a voltage of the same phase between the plurality of piezoelectric bodies are provided, the plurality of beams contact the rotating body substantially simultaneously. Therefore, a large torque can be obtained.

Further, in the piezoelectric actuator of the present invention, the rotary moving body, a plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end are spread for each of the beam portions. A vibrating body composed of a plurality of piezoelectric bodies, a power supply for applying a voltage to each of the plurality of piezoelectric bodies, and a phase control of the voltage between the piezoelectric bodies when applying a voltage from the power supply to each of the plurality of piezoelectric bodies. And the phase control means for performing the above operation, the rotating moving body can be effectively rotated.

In the piezoelectric actuator of the present invention, the phase control means applies a voltage to each of the plurality of piezoelectric bodies, and applies a voltage having the same phase between the case where a phase difference is given to the voltage between the piezoelectric bodies. Since the switching means is provided for switching between the case and the case where the rotation is performed, the rotary moving body can be effectively rotated.

Further, in the piezoelectric actuator of the present invention, the rotary moving body, a plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end are spread for each of the beam portions. Since a vibrating body composed of a plurality of piezoelectric bodies, a power supply for applying a voltage to each of the plurality of piezoelectric bodies, and a voltage control means for controlling a voltage applied from the power supply to each of the plurality of piezoelectric bodies, The rotating moving body can be effectively rotated.

In the method of controlling a piezoelectric actuator according to the present invention, a plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end, and a plurality of piezoelectric members spread on the beam portions are provided. When a vibrating body is formed from this, a voltage is applied to the piezoelectric body to vibrate the beam, and the beam is brought into contact with the rotating body to rotate the rotating body. The same phase voltage is applied between the plurality of piezoelectric bodies, and during normal rotation, control is performed so as to give a phase difference to the voltage applied between the plurality of piezoelectric bodies, so that the rotating moving body can be effectively rotated. it can.

Further, in the piezoelectric actuator of the present invention, the plurality of beams extending in the tangential direction of the inner circle of the rotary moving body and fixed at one end and free at the other end, and the plurality of piezoelectric members spread on the beams are used. Forming a body, applying a voltage to the piezoelectric body to vibrate a beam, and rotating the rotary moving body by bringing the beam into contact with the rotary moving body,
At the time of rotation start, a high voltage is applied to the plurality of piezoelectric bodies, and at the time of normal rotation, a control is performed so as to apply a low voltage to the plurality of piezoelectric bodies. Therefore, the rotary moving body can be rotated effectively.

In the computer-readable storage medium according to the present invention, a program for causing a computer to execute the above-described method for controlling a piezoelectric actuator is stored. Can be rotated effectively.

[Brief description of the drawings]

FIG. 1 is an assembly diagram showing a rotary actuator according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram showing a detailed structure of a vibrating body block shown in FIG.

FIG. 3 is a block diagram showing a phase control unit of the micro piezoelectric motor according to Embodiment 2 of the present invention.

FIG. 4 is an explanatory diagram showing a timing chart of the phase control.

FIG. 5 is an explanatory diagram showing a timing chart of phase control.

FIG. 6 is a block diagram showing a voltage control unit of a micro piezoelectric motor according to Embodiment 3 of the present invention.

FIG. 7 is a graph showing a voltage control state.

FIG. 8 is a block diagram showing a drive control unit of a micro piezoelectric motor according to Embodiment 4 of the present invention.

FIG. 9 is a block diagram showing a drive control unit of a micro piezoelectric motor according to Embodiment 5 of the present invention.

FIG. 10 is an assembly view showing an example of a conventional micro piezoelectric motor.

FIG. 11 is an explanatory diagram showing the operation principle of the micro piezoelectric motor shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Rotary actuator 1 Rotary moving body 11 Shaft protrusion 12 Sliding part 2 Vibrating body block 21 Bending displacement mechanism 23 Piezoelectric element 24 Beam 3 Base chassis 101 Signal generator 102 Phase controller 103 Driver 104 Voltage controller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Satoshi Sato 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside of Eiko Instruments Inc. Iko Instruments Inc.

Claims (11)

[Claims] 1. A rotating body, a plurality of beams extending in the tangential direction of an inner circle of the rotating body and having one end fixed and free from the other end, and a plurality of piezoelectric bodies spread for each beam. A vibrating body, comprising: a power supply for applying a voltage to the plurality of piezoelectric bodies, wherein the power supply is a power supply for applying a voltage having a phase difference between the plurality of piezoelectric bodies. Characterized piezoelectric actuator. 2. A power supply for applying a voltage having a phase difference, wherein the phase difference between the plurality of piezoelectric bodies is a reciprocal of a number obtained by doubling the total number of the beam portions. Piezoelectric actuator. 3. A rotary moving body, comprising: a plurality of beam portions extending in the direction of an inner circle tangent to the rotary moving body and fixed at one end and free at the other end; and a plurality of piezoelectric members spread for each of the beam portions. A vibrating body, and a power supply for applying a voltage to the plurality of piezoelectric bodies, wherein the power supply is a power supply for applying an in-phase voltage to all of the plurality of piezoelectric bodies. A piezoelectric actuator characterized in that: 4. A rotating body, a plurality of beam portions extending in an inner circle tangential direction of the rotating body and having one end fixed and free from the other end, and a plurality of piezoelectric bodies spread for each beam portion. A piezoelectric actuator comprising: a vibrating body; a drive control circuit capable of applying a drive voltage to each of the plurality of piezoelectric bodies; and a power supply for supplying a voltage to the drive control circuit. 5. The piezoelectric actuator according to claim 4, wherein the drive control means is a drive control circuit having a phase control means for performing phase control of a drive voltage applied to each of the plurality of piezoelectric bodies. 6. A drive control circuit having switching means for switching between a case in which drive voltages applied to each of a plurality of piezoelectric bodies are applied in the same phase and a case in which a drive voltage is applied with a phase difference. The piezoelectric actuator according to claim 4, wherein the piezoelectric actuator is provided. 7. The drive control circuit according to claim 4, wherein the drive control means is a drive control circuit having voltage control means for controlling a drive voltage applied to each of the plurality of piezoelectric bodies. The piezoelectric actuator according to claim 1. 8. A vibrating body is formed from a plurality of beam portions extending in the inner circle tangent direction of the rotary moving body and fixed at one end and free at the other end, and a plurality of piezoelectric bodies spread on the beam portions. When a voltage is applied to the body to vibrate the beam, and the beam is brought into contact with the rotating body to rotate the rotating body, a voltage of the same phase is applied between the plurality of piezoelectric bodies at the start of rotation. And controlling the piezoelectric actuator to apply a phase difference to a voltage applied between the plurality of piezoelectric bodies during normal rotation. 9. A vibrating body is formed from a plurality of beam portions extending in the inner circle tangential direction of the rotary moving body and fixed at one end and free at the other end, and a plurality of piezoelectric members spread on the beam portions. When a voltage is applied to the body to vibrate the beam, and the beam is brought into contact with the rotating body to rotate the rotating body, a voltage applied between the plurality of piezoelectric bodies at a constant speed rotation A phase difference between the voltages applied between the plurality of piezoelectric bodies during acceleration and deceleration. 10. A vibrating body is formed from a plurality of beam portions extending in the inner circle tangent direction of the rotary moving body and fixed at one end and free at the other end, and a plurality of piezoelectric bodies spread on the beam portions. A voltage is applied to the body to vibrate the beam, and the beam is brought into contact with the rotating body to rotate the rotating body. At the time of rotation start, a high voltage is applied to the plurality of piezoelectric bodies. And controlling the piezoelectric actuator so as to apply a low voltage to the plurality of piezoelectric bodies during normal rotation. 11. A computer-readable storage medium storing a program for causing a computer to execute the method for controlling a piezoelectric actuator according to claim 8.