JP2636280B2 - Driving method of ultrasonic motor - Google Patents
Driving method of ultrasonic motorInfo
- Publication number
- JP2636280B2 JP2636280B2 JP62307866A JP30786687A JP2636280B2 JP 2636280 B2 JP2636280 B2 JP 2636280B2 JP 62307866 A JP62307866 A JP 62307866A JP 30786687 A JP30786687 A JP 30786687A JP 2636280 B2 JP2636280 B2 JP 2636280B2
- Authority
- JP
- Japan
- Prior art keywords
- ultrasonic motor
- voltage
- output
- driving
- amplifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 7
- 239000000919 ceramic Substances 0.000 description 13
- 238000005452 bending Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 239000002783 friction material Substances 0.000 description 3
- 230000004913 activation Effects 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
- H02N2/10—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors
- H02N2/14—Drive circuits; Control arrangements or methods
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
- H02N2/10—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors
- H02N2/16—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing rotary motion, e.g. rotary motors using travelling waves, i.e. Rayleigh surface waves
- H02N2/163—Motors with ring stator
Landscapes
- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は圧電体を用いて駆動力を発生する超音波モー
タの駆動法に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method of an ultrasonic motor that generates a driving force by using a piezoelectric body.
従来の技術 近年圧電セタミック等の圧電体を用いた振動体に弾性
振動を励振し、これを駆動力とした超音波モータが注目
されている。2. Description of the Related Art In recent years, an ultrasonic motor that excites an elastic vibration in a vibrating body using a piezoelectric body such as a piezoelectric setamic and uses the vibration as a driving force has attracted attention.
以下、図面を参照しながら超音波モータの従来技術に
ついて説明を行う。Hereinafter, a conventional technique of an ultrasonic motor will be described with reference to the drawings.
第３図は従来の超音波モータの斜視図であり、の弾性
体11の円環面の一方に圧電体としての圧電セラミック10
を貼り合わせて振動体12を構成している。13は耐磨耗性
材料の摩擦材、14は弾性体であり、互いに貼り合わせて
移動体15を構成している。移動体15は、摩擦材13を介し
て振動体12と接触している。圧電セラミック10に電界を
印加すると振動体12の周方向に曲げ振動の進行波が励起
され、移動体15を駆動する。尚、同図中の矢印は移動体
15の回転方向を示す。FIG. 3 is a perspective view of a conventional ultrasonic motor, in which a piezoelectric ceramic 10 as a piezoelectric body is provided on one of the annular surfaces of an elastic body 11.
Are bonded to form the vibrating body 12. Reference numeral 13 denotes a friction material made of an abrasion-resistant material, and reference numeral 14 denotes an elastic body. The moving body 15 is in contact with the vibrating body 12 via the friction material 13. When an electric field is applied to the piezoelectric ceramic 10, a traveling wave of bending vibration is excited in the circumferential direction of the vibrating body 12 to drive the moving body 15. The arrow in FIG.
15 rotation directions are shown.
第４図は第３図の超音波モータに使用した圧電セラミ
ック10の電極構造の一例を示している。同図では円周方
向に９波の弾性波がのるようにしてある。同図におい
て、ＡおよびＢはそれぞれ２分の１波長相当の小領域か
ら成る電極群で、Ｃは４分の３波長、Ｄは４分の１波長
の長さの電極である。電極ＣおよびＤは電極群ＡとＢに
位置的に４分の１波長（＝90度）の位相差を作ってい
る。電極ＡとＢ内の隣り合う小電極部は互いに反対に厚
み方向に分極されている。圧電セラミック10の弾性体11
との接着面は、第４図に示めされた面と反対の面であ
り、電極はベタ電極である。使用時には、電極群Ａおよ
びＢは第４図に斜線で示されたように、それぞれ短絡し
て用いられる。FIG. 4 shows an example of the electrode structure of the piezoelectric ceramic 10 used in the ultrasonic motor of FIG. In the figure, nine elastic waves are applied in the circumferential direction. In the figure, A and B are electrode groups each composed of a small area corresponding to a half wavelength, C is an electrode having a length of 3/4 wavelength, and D is an electrode having a length of a quarter wavelength. The electrodes C and D form a phase difference of a quarter wavelength (= 90 degrees) between the electrode groups A and B in position. The adjacent small electrode portions in the electrodes A and B are polarized in the thickness direction opposite to each other. Elastic body 11 of piezoelectric ceramic 10
4 is opposite to the surface shown in FIG. 4, and the electrode is a solid electrode. In use, the electrode groups A and B are short-circuited, respectively, as shown by oblique lines in FIG.
以上のように構成された超音波モータの圧電セラミッ
ク10の電極ＡおよびＢに、 V1＝V0×sin（ωｔ） ……（１） V2＝V0×cos（ωｔ） ……（２） ただし、V0:電圧の瞬時値 ω：角周波数 t:時間 で表される電圧V1およびV2をそれぞれ印加すれば、振動
体12には、 ξ＝ξ０×（cos（ωｔ）×cos（kx） ＋sin（ωｔ）×sin（kx）） ＝ξ０×cos（ωｔ−kx） ……（２） ただし ξ：曲げ振動の振幅値 ξ0:曲げ振動の瞬時値 k:波数（２π／λ） λ：波長 x:位置 で表せる、円周方向に進行する曲げ振動の進行波が励起
される。V 1 = V 0 × sin (ωt) (1) V 2 = V 0 × cos (ωt) (2) is applied to the electrodes A and B of the piezoelectric ceramic 10 of the ultrasonic motor configured as described above. Here, V 0 : instantaneous value of voltage ω: angular frequency t: time When voltages V 1 and V 2 represented by time are applied, respectively, 振動 = 体0 × (cos (ωt) × cos (kx) + sin (ωt ) × sin (kx)) = ξ 0 × cos (ωt-kx) ...... (2) where ξ: bending amplitude value of the vibration ξ 0: instantaneous value of the bending vibration k: wave number (2π / Λ) λ: wavelength x: position Exciting a traveling wave of bending vibration that travels in the circumferential direction and can be expressed by:
第５図は振動体12の表面のＡ点が進行波の励起によっ
て、長軸2w、短軸2uの楕円運動をし、振動体12上に加圧
して設置された移動体15が、楕円の頂点近傍で接触する
ことにより、摩擦力により波の進行方向とは逆方向にｖ
＝ω×ｕの速度で運動する様子を示している。FIG. 5 shows that the point A on the surface of the vibrating body 12 performs an elliptical motion of a long axis 2w and a short axis 2u by excitation of a traveling wave, and a moving body 15 placed under pressure on the vibrating body 12 has an elliptical shape. By contact near the vertex, frictional force causes v
= Ω x u.
発明が解決しようとする問題点 超音波モータの出力を大きくするためには、振動体の
持っている運動エネルギーを大きくすればよい。運動エ
ネルギーは振動体の質量と速度の２乗に比例するので、
振動体の質量または速度を増やせば出力を増加できる。
尚、蒸気速度ｖは、振動体12の曲げ振動の瞬時値ξ０に
比例し、曲げ振動の瞬時値ξ０は、振動体12を構成する
圧電セラミック10に流れる電流値に比例するため、小さ
な電圧で大きな電流が得られる振動体12の共振周波数近
傍で駆動すれば、大きな速度が得られ、超音波モータの
出力を大きくすることができる。しかし、超音波モータ
の共振周波数は負荷によって変動するため、低トルク出
力時では、駆動周波数が共振周波数近傍からずれていて
も、起動しやすいが、高トルク出力時では、駆動周波数
が共振周波数近傍からずれていると、起動しにくいとい
う問題点がある。Problems to be Solved by the Invention In order to increase the output of the ultrasonic motor, the kinetic energy of the vibrator may be increased. Since the kinetic energy is proportional to the square of the mass and velocity of the oscillator,
The output can be increased by increasing the mass or speed of the vibrator.
Since steam velocity v is proportional to the instantaneous value xi] 0 of the bending vibration of the vibrating body 12, the instantaneous value xi] 0 of the bending vibration is proportional to the current flowing through the piezoelectric ceramic 10 constituting the vibrator 12, a small If the vibrator 12 is driven near the resonance frequency where a large current can be obtained with a voltage, a large speed can be obtained and the output of the ultrasonic motor can be increased. However, since the resonance frequency of the ultrasonic motor fluctuates depending on the load, it is easy to start at low torque output even if the drive frequency deviates from the vicinity of the resonance frequency, but at high torque output, the drive frequency is near the resonance frequency. If it deviates, there is a problem that it is difficult to start.
本発明はかかる点に鑑みてなされたもので、出力する
トルクに拘らず安定した起動ができ、しかも効率の良い
超音波モータを提供することを目的としている。The present invention has been made in view of the above, and an object of the present invention is to provide an ultrasonic motor that can start stably irrespective of the output torque and that is efficient.
問題点を解決するための手段 出力させるトルクに応じて、動作時の印加電圧に対す
る起動時の印加電圧の高さを制御する超音波モータの駆
動法を用いる。Means for Solving the Problems An ultrasonic motor driving method is used in which the height of the applied voltage at the time of startup with respect to the applied voltage during operation is controlled according to the torque to be output.
作 用 出力させるトルクに応じて、動作時の印加電圧に対し
て、起動時の印加電圧を高くすることによって、高トル
ク出力時でも、起動しやすく、効率の良い安定した超音
波モータの駆動ができる。Operation By increasing the applied voltage at start-up relative to the applied voltage during operation according to the torque to be output, it is easy to start even at high torque output, and efficient and stable driving of the ultrasonic motor is achieved. it can.
実施例 以下、図面に従って本発明の一実施例について詳細な
説明を行う。Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
第１図は本発明の一実施例である超音波モータ駆動回
路のブロック図である。超音波モータの起動信号を発す
る起動制御部１は、発振器２に接続されており、発振器
２の出力は、一方で90度移相器３を介して、外部からの
信号により増幅率を変化させることができる電圧制御増
幅器A4に、他方では電圧制御増幅器B5に接続されてい
る。電圧制御増幅器A4の出力側は、抵抗R16を介して超
音波モータの駆動体を構成する圧電セラミック10に印加
され、電圧制御増幅器B5の出力側は、抵抗R27を介して
上記圧電セラミック10に印加される。また、抵抗R16の
両端では差動増幅器A7の２つの入力側と接続しており、
差動増幅器A7の出力側は電圧制御増幅器A4に接続してい
る。同様に、抵抗R28の両端では差動増幅器B9の２つの
入力側に接続しており、差動増幅器B9の出力側は電圧制
御増幅器B5に接続している。第２図（ａ）は、トルクの
変化に対する、第１図に於ける抵抗R1及び抵抗R2に流れ
る電流の変化を表しており、第２図（ｂ）は、トルクの
変化に対する差動増幅器A7、及び差動増幅器B9の出力信
号を表している。FIG. 1 is a block diagram of an ultrasonic motor driving circuit according to one embodiment of the present invention. A start control unit 1 for generating a start signal of the ultrasonic motor is connected to the oscillator 2, and the output of the oscillator 2 changes the amplification factor by a signal from the outside via the 90-degree phase shifter 3. Connected to a voltage-controlled amplifier A4, on the other hand, and to a voltage-controlled amplifier B5 on the other hand. The output side of the voltage controlled amplifier A4 via a resistor R 1 6 is applied to the piezoelectric ceramic 10 which constitutes the drive of the ultrasonic motor, the output of the voltage controlled amplifier B5, the piezoelectric via the resistor R 2 7 Applied to ceramic 10. Further, the both ends of the resistor R 1 6 is connected to the two inputs of the differential amplifier A7,
The output side of the differential amplifier A7 is connected to the voltage control amplifier A4. Similarly, both ends of the resistor R 2 8 are connected to the two inputs of the differential amplifier B9, the output of the differential amplifier B9 is connected to the voltage control amplifier B5. Figure 2 (a) is, with respect to a change in the torque indicates a change in the current flowing in the first figure in resistors R 1 and R 2, FIG. 2 (b), the differential with respect to a change in torque The output signals of the amplifier A7 and the differential amplifier B9 are shown.
第１図に於いて、上記起動制御部１から起動信号が発
せられると、上記発振器２から駆動周波数の信号が発せ
られる。ここで、上記信号は２分割され、一方は上記90
度移相器３を通り、上記電圧制御増幅器A4によって、上
記超音波モータを駆動する電圧に昇圧される。他方、該
信号は上記電圧制御増幅器B5によって、上記電圧に昇圧
される。更に、上記電圧制御増幅器A4から発せられた信
号は上記抵抗R16を通って、上記圧電セラミック10に印
加される。ここで、第２図（ａ）に示したように、上記
抵抗R16を流れる電流が出力するトルクによって変化し
た場合、上記差動増幅器A7が上記電流の変化を検出し、
上記電圧制御増幅器A4に信号を発する。該信号によっ
て、上記電圧制御増幅器A4の出力が変化し、第２図
（ｂ）に示したように、起動時にはS1、駆動時にはS2の
ような電圧が圧電セラミック10に印加される。同様に、
上記抵抗R28を流れる電流が出力するトルクによって変
化した場合、上記差動増幅器B9が上記電流の変化を検出
し、上記電圧制御増幅器B5に信号を発する。該信号によ
って、上記電圧制御増幅器B5の出力が変化し、第３図
（ｂ）に示したように、起動時にはS1、駆動時にはS2の
ような電圧が圧電セラミック10に印加される。以上のよ
うな超音波モータの駆動制御法により、出力させるトル
クに応じて起動時の印加電圧が変化するため、高トルク
出力時でも、安定し、かつ効率良く駆動ができる。In FIG. 1, when an activation signal is issued from the activation control unit 1, a signal of a driving frequency is emitted from the oscillator 2. Here, the signal is divided into two parts, one of which is divided into 90 parts.
After passing through the phase shifter 3, the voltage is increased to a voltage for driving the ultrasonic motor by the voltage control amplifier A4. On the other hand, the signal is boosted to the voltage by the voltage control amplifier B5. Furthermore, the signal emitted from the voltage control amplifier A4 is through the resistor R 1 6, is applied to the piezoelectric ceramic 10. Here, as shown in FIG. 2 (a), when changed by the torque current flowing through the resistor R 1 6 is output, the differential amplifier A7 detects a change in the current,
A signal is issued to the voltage control amplifier A4. By the signal, the output of the voltage controlled amplifier A4 is changed, as shown in FIG. 2 (b), S 1 at the time of startup, the drive voltage such as S 2 is applied to the piezoelectric ceramic 10. Similarly,
If changed by the torque output by the electric current flowing through the resistor R 2 8, the differential amplifier B9 detects a change in the current, emits a signal to the voltage control amplifier B5. By the signal, the output of the voltage controlled amplifier B5 is changed, as shown in FIG. 3 (b), S 1 at the time of startup, the drive voltage such as S 2 is applied to the piezoelectric ceramic 10. According to the driving control method of the ultrasonic motor as described above, the applied voltage at the time of startup changes according to the torque to be output, so that stable and efficient driving can be performed even at the time of high torque output.
発明の効果 本発明によれば、高トルク出力時でも、安定した効率
の良い超音波モータを提供できる。According to the present invention, a stable and efficient ultrasonic motor can be provided even at the time of high torque output.
【図面の簡単な説明】 第１図は本発明の一実施例における超音波モータの駆動
法を用いた駆動回路のブロック図、第２図は第１図の実
施例に於けるトルクに対する各信号を示す特性図、第３
図は従来の超音波モータの斜視図、第４図は第３図の超
音波モータに用いた圧電セラミックの形状及び、電極構
造を示す平面図、第５図は超音波モータの動作原理の説
明図である。 １……起動制御部、２……発振器、３……90度移相器、
４……電圧制御増幅器Ａ、５……電圧制御増幅器Ｂ、６
……抵抗R1、７……差動増幅器Ａ、８……抵抗R2、９…
…差動増幅器Ｂ、10……圧電セラミック、11……弾性
体、12……振動体、13……摩擦材、14……弾性体、15…
…移動体。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a drive circuit using a driving method of an ultrasonic motor according to an embodiment of the present invention, and FIG. 2 is a diagram showing signals for torque in the embodiment of FIG. FIG.
FIG. 4 is a perspective view of a conventional ultrasonic motor, FIG. 4 is a plan view showing the shape and electrode structure of a piezoelectric ceramic used in the ultrasonic motor of FIG. 3, and FIG. FIG. 1. Startup control unit 2. Oscillator 3. 90 degree phase shifter
4 ... voltage controlled amplifier A, 5 ... voltage controlled amplifier B, 6
...... resistors R 1, 7 ...... differential amplifier A, 8 ...... resistor R 2, 9 ...
... Differential amplifier B, 10 ... Piezoelectric ceramic, 11 ... Elastic body, 12 ... Vibration body, 13 ... Friction material, 14 ... Elastic body, 15 ...
... moving body.
Claims (1)
と弾性体とから構成される振動体に弾性進行波を励振す
ることにより、前記振動体上に接触して設置された移動
体を移動させる超音波モータの駆動法において、前記超
音波モータに流れる電流の変化を検出することにより、
前記超音波モータへの印加電圧を動作時の印加電圧に対
して、出力するトルクに応じて起動時の印加電圧の高さ
を制御することを特徴とする超音波モータの駆動法。A moving member disposed in contact with the vibrating body by driving the piezoelectric body with an AC voltage to excite a vibrating body composed of the piezoelectric body and the elastic body with an elastic traveling wave; In the driving method of the ultrasonic motor to move the body, by detecting a change in the current flowing through the ultrasonic motor,
A method of driving an ultrasonic motor, comprising: controlling a height of an applied voltage at the time of starting the applied voltage to the ultrasonic motor in accordance with a torque to be output with respect to an applied voltage at the time of operation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62307866A JP2636280B2 (en) | 1987-12-04 | 1987-12-04 | Driving method of ultrasonic motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62307866A JP2636280B2 (en) | 1987-12-04 | 1987-12-04 | Driving method of ultrasonic motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01148082A JPH01148082A (en) | 1989-06-09 |
| JP2636280B2 true JP2636280B2 (en) | 1997-07-30 |
Family
ID=17974106
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62307866A Expired - Lifetime JP2636280B2 (en) | 1987-12-04 | 1987-12-04 | Driving method of ultrasonic motor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2636280B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3241713B2 (en) * | 1988-12-23 | 2001-12-25 | 株式会社ニコン | Drive control circuit of ultrasonic motor and ultrasonic motor |
| JP5277010B2 (en) * | 2009-02-09 | 2013-08-28 | パナソニック株式会社 | Drive device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5989585A (en) * | 1982-11-15 | 1984-05-23 | Yoshiaki Komatsu | Auxiliary circuit for starting motor |
-
1987
- 1987-12-04 JP JP62307866A patent/JP2636280B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5989585A (en) * | 1982-11-15 | 1984-05-23 | Yoshiaki Komatsu | Auxiliary circuit for starting motor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01148082A (en) | 1989-06-09 |
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