JP2010253361A

JP2010253361A - Vibration type driving device and method of controlling the same

Info

Publication number: JP2010253361A
Application number: JP2009105114A
Authority: JP
Inventors: Kazuhiro Shibatani; 一弘柴谷
Original assignee: Konica Minolta Opto Inc
Current assignee: Konica Minolta Opto Inc
Priority date: 2009-04-23
Filing date: 2009-04-23
Publication date: 2010-11-11

Abstract

PROBLEM TO BE SOLVED: To provide a vibration type driving device capable of detecting that a moving body has reaches a movable end in a simple configuration. SOLUTION: In the vibration type driving device 1 including an electromechanical conversion element 7, a driving member 8 vibrated by the electromechanical conversion element 7, a moving body 9 in frictional engagement with the driving member 8, regulating members 10, 11 capable of limiting the relative movement of the moving body 9 by being abutted to the moving body 9, and a driving circuit 3 for applying a cyclic driving voltage to the electromechanical conversion element 7, a phase difference between the driving voltage and a current flowing through the electromechanical conversion element 7 is detected by a phase difference detection circuit 4, and when the phase difference is in a prescribed range, it is determined that the moving body 9 is abutted to the regulating members 10, 11. COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、振動型駆動装置および振動型駆動装置の制御方法に関する。 The present invention relates to a vibration type driving apparatus and a method for controlling the vibration type driving apparatus.

電気機械変換素子によって駆動部材を軸方向に非対称に振動させて、駆動部材に摩擦係合する移動体を駆動軸に対して滑り変位させる振動型の駆動装置が公知である。振動型の駆動装置では、電気機械変換素子に印加する駆動電圧の１周期当たりの移動体の変位量が、厳密には一定でなく、実際の移動体の位置が、駆動電圧から推定される位置からずれてしまう場合がある。このため、従来の振動型駆動装置で位置決めを行う場合、特許文献１に記載されているように、移動体の位置を検出するセンサを設ける必要があった。 2. Description of the Related Art A vibration type driving device is known in which a driving member is asymmetrically vibrated in an axial direction by an electromechanical conversion element, and a moving body frictionally engaged with the driving member is slidably displaced with respect to the driving shaft. In the vibration type driving device, the displacement amount of the moving body per cycle of the driving voltage applied to the electromechanical transducer is not strictly constant, and the actual position of the moving body is estimated from the driving voltage. May be off. For this reason, when performing positioning with a conventional vibration type driving device, it is necessary to provide a sensor for detecting the position of the moving body as described in Patent Document 1.

また、簡易な構成として、移動体に当接して移動体の可動範囲を定める部材を設け、移動体を可動範囲よりも十分に長い距離を移動させ得るだけの駆動電圧を印加することで、一度、移動体を可動範囲の一端に移動させ、この可動端を基点として、所望の位置まで移動体を移動させるだけの駆動電圧を印加することで、移動体の位置決め誤差を抑制するものもある。しかしながら、この構成では、移動体が可動端に達してからも、一定時間は駆動電圧を印加し続けることが必要であり、駆動に時間がかかるという問題がある。 In addition, as a simple configuration, a member that abuts the moving body to determine the movable range of the moving body is provided, and a driving voltage that can move the moving body by a distance sufficiently longer than the movable range is applied once. In some cases, the movable body is moved to one end of the movable range, and a driving voltage for moving the movable body to a desired position is applied using the movable end as a base point to suppress the positioning error of the movable body. However, with this configuration, it is necessary to continue to apply the driving voltage for a certain time after the moving body reaches the movable end, and there is a problem that it takes time to drive.

例えば、２つの振動型駆動装置によって、移動体をＸ−Ｙ方向に走査移動させる場合、１走査毎に移動体を可動端まで移動させる必要があり、このような余分な駆動時間が積み重なって大きなタイムロスとなる。 For example, when the moving body is scanned and moved in the XY direction by two vibration type driving devices, it is necessary to move the moving body to the movable end for each scan, and such extra driving time is accumulated and becomes large. Time loss.

余分な駆動時間をなくすために、移動体が可動端に達したことを検出できるセンサを設けることが考えられるが、センサの検出精度が装置の位置決め精度に直結するので、高価なセンサを使用する必要があり、大きなコストアップは避けられない。 In order to eliminate extra driving time, it is conceivable to provide a sensor that can detect that the moving body has reached the movable end. However, since the detection accuracy of the sensor is directly linked to the positioning accuracy of the device, an expensive sensor is used. It is necessary and a large cost increase is inevitable.

特開２０００−７８８６１号公報JP 2000-78861 A

前記問題点に鑑みて、本発明は、簡単な構成で、移動体が可動端に達したことを検知し得る振動型駆動装置を提供することを課題とする。 In view of the above problems, an object of the present invention is to provide a vibration type driving device that can detect that a moving body has reached a movable end with a simple configuration.

前記課題を解決するために、本発明による振動型駆動装置は、電気機械変換素子と、電気機械変換素子によって振動させられる駆動部材と、前記駆動部材に摩擦係合する移動体と、前記移動体と当接して前記移動体の相対移動を制限し得る規制部材と、前記電気機械変換素子に周期的な駆動電圧を印加する駆動回路と、前記駆動電圧と、前記電気機械変換素子を流れる電流との位相差を検出する位相差検出手段と、前記位相差が所定の範囲にあるとき、前記移動体が前記規制部材に当接していると判断する判定手段とを有するものとする。 In order to solve the above problems, a vibration type driving apparatus according to the present invention includes an electromechanical conversion element, a driving member that is vibrated by the electromechanical conversion element, a moving body that frictionally engages the driving member, and the moving body. A regulating member capable of restricting relative movement of the moving body in contact with the movable body, a drive circuit for applying a periodic drive voltage to the electromechanical transducer, the drive voltage, and a current flowing through the electromechanical transducer A phase difference detecting means for detecting the phase difference of the first position and a determining means for determining that the moving body is in contact with the regulating member when the phase difference is in a predetermined range.

この構成によれば、移動体が規制部材に当接することで、電気機械変換素子が駆動する駆動部材の見かけ上の質量が大きくなって振動系の周波数特性が変化する。このため、電気機械変換素子の力率が変化して、駆動電圧と電流との位相差が変化するので、位相差によって移動体が規制部材に当接していることを検出できる。移動体を規制部材に当接させることで原点復帰し、駆動電圧から推定される移動体の位置と、実際の移動体の位置との誤差をなくすことによって、移動体の位置決め精度を確保できる。 According to this configuration, when the moving body comes into contact with the regulating member, the apparent mass of the driving member driven by the electromechanical conversion element is increased, and the frequency characteristic of the vibration system is changed. For this reason, since the power factor of the electromechanical conversion element changes and the phase difference between the drive voltage and the current changes, it can be detected that the moving body is in contact with the regulating member by the phase difference. By returning the origin by bringing the moving body into contact with the regulating member and eliminating the error between the position of the moving body estimated from the drive voltage and the actual position of the moving body, the positioning accuracy of the moving body can be ensured.

また、本発明の振動型駆動装置において、前記駆動回路は、前記位相差を検出する際、前記駆動電圧の周波数を、前記移動体が前記規制部材に当接していない状態で前記駆動部材の変位が最大となる共振周波数としてもよい。 In the vibration type driving device according to the aspect of the invention, when the driving circuit detects the phase difference, the driving circuit sets the frequency of the driving voltage in a state where the moving body is not in contact with the regulating member. It is good also as a resonant frequency which becomes the maximum.

このような振動系では、周波数変化に対する電流の位相の変化率が共振点付近で最大となるので、共振周波数の駆動電圧を用いることで、移動体が規制部材に当接することによる周波数特性の変化によって生じる位相差の変化が大きくなる。 In such a vibration system, since the rate of change of the phase of the current with respect to the frequency change becomes maximum near the resonance point, the frequency characteristics change due to the moving body abutting against the regulating member by using the drive voltage of the resonance frequency The change in the phase difference caused by is increased.

また、本発明の振動型駆動装置において、前記駆動回路は、前記位相差を検出する際、前記駆動電圧をデューティ比５０％の矩形波電圧とし、前記判定手段は、前記駆動電圧に対する前記電流の位相の遅れが所定の値以上になったとき、前記移動体が前記規制部材に当接していると判断してもよい。 In the vibration type driving device of the present invention, when the driving circuit detects the phase difference, the driving voltage is a rectangular wave voltage with a duty ratio of 50%, and the determination unit is configured to output the current with respect to the driving voltage. When the phase delay is equal to or greater than a predetermined value, it may be determined that the moving body is in contact with the regulating member.

この構成によれば、駆動電圧を矩形波にしたことで、駆動回路が直流電源のスイッチングを行うだけの簡単な構成となる。また、駆動電圧のデューティ比を５０％にすれば高調波成分が最も小さくなるので、振動系の周波数特性の変化による電流の位相の変化が検出しやすくなる。さらに、共振点における電気機械変換素子の力率は１００％であるため、移動体が規制部材に当接していないときに検出される位相差はゼロである。そして、移動体が規制部材に当接すると振動系の質量増加によって共振点が低くなり、共振点より高い周波数では電流の位相が遅れるので、電流の位相が駆動電圧に対して遅れたときは、移動体が規制部材に当接していると判断できる。 According to this configuration, since the drive voltage is a rectangular wave, the drive circuit can be simply configured to switch the DC power supply. Further, when the duty ratio of the drive voltage is set to 50%, the harmonic component becomes the smallest, so that the change in the phase of the current due to the change in the frequency characteristic of the vibration system can be easily detected. Furthermore, since the power factor of the electromechanical transducer at the resonance point is 100%, the phase difference detected when the moving body is not in contact with the regulating member is zero. When the moving body comes into contact with the regulating member, the resonance point becomes low due to the increase in mass of the vibration system, and the phase of the current is delayed at a frequency higher than the resonance point, so when the phase of the current is delayed with respect to the drive voltage, It can be determined that the moving body is in contact with the regulating member.

また、本発明の振動型駆動装置において、前記駆動回路は、前記位相差を検出する際、駆動電圧の波高を低くしてもよい。 Further, in the vibration type driving device of the present invention, the driving circuit may reduce the wave height of the driving voltage when detecting the phase difference.

この構成によれば、位相差検出のために消費する電力を低減できる。 According to this configuration, power consumed for phase difference detection can be reduced.

また、本発明による、電気機械変換素子と、電気機械変換素子によって振動させられる駆動部材と、前記駆動部材に摩擦係合する移動体と、前記移動体と当接して前記移動体の移動を制限し得る規制部材とを有する振動型駆動装置の制御方法は、前記電気機械変換素子に印加する駆動電圧と、前記電気機械変換素子を流れる電流との位相差が所定の範囲にあるとき、前記移動体が前記規制部材に当接していると判断する方法とする。 In addition, according to the present invention, an electromechanical conversion element, a driving member that is vibrated by the electromechanical conversion element, a moving body that frictionally engages the driving member, and a movement member that abuts on the moving body to limit the movement of the moving body. The control method of the vibration type drive device having a regulating member capable of performing the movement when the phase difference between the drive voltage applied to the electromechanical transducer and the current flowing through the electromechanical transducer is within a predetermined range. A method of determining that the body is in contact with the restriction member is used.

この方法によれば、センサを設けずとも、移動体の原点復帰を検出でき、移動体の原点復帰のために必要以上の駆動電圧を印加する必要がなく、移動体の位置決めを迅速に行うことができる。 According to this method, it is possible to detect the return to origin of the moving body without providing a sensor, and it is not necessary to apply an excessive driving voltage for returning the origin of the moving body, and the moving body can be positioned quickly. Can do.

また、本発明の振動型駆動装置の制御方法において、記位相差の検出は、前記移動体を移動させる必要がないときに、前記駆動電圧の波形を、前記移動体を移動させるときと異ならせて行ってもよい。 Further, in the control method of the vibration type driving device of the present invention, the detection of the phase difference is performed by making the waveform of the driving voltage different from that when the moving body is moved when it is not necessary to move the moving body. You may go.

この方法によれば、移動体の駆動と移動体の原点復帰の検出とにそれぞれ駆動電圧を最適化することで、振動型駆動装置を高トルク且つ高精度に使用できる。 According to this method, the vibration type driving device can be used with high torque and high accuracy by optimizing the driving voltage for driving the moving body and detecting the return to origin of the moving body.

また、本発明の振動型駆動装置の制御方法において、前記移動体の移動を停止する度に、前記位相差を検出してもよい。 In the control method of the vibration type driving device of the present invention, the phase difference may be detected every time the movement of the moving body is stopped.

この方法によれば、移動体の移動が終わる度に、移動体が可動端に達していないか確認するので、移動体をさらに規制部材に押し当てる無駄な駆動をなくすことができる。 According to this method, every time the moving body finishes moving, it is confirmed whether the moving body has reached the movable end, and therefore it is possible to eliminate useless driving for further pressing the moving body against the regulating member.

以上のように、本発明によれば、移動体が規制部材に当接したときに、振動系の周波数特性が変化することにより生じる駆動電圧と電流との位相差の変化を検出することで、移動体が可動端に達したことを確認できるので、無駄な駆動電圧の印加をなくし、迅速且つ正確な移動体の位置決めができる。 As described above, according to the present invention, by detecting the change in the phase difference between the drive voltage and the current that occurs when the frequency characteristic of the vibration system changes when the moving body comes into contact with the regulating member, Since it can be confirmed that the moving body has reached the movable end, it is possible to eliminate the useless application of the driving voltage and to quickly and accurately position the moving body.

本発明の一実施形態の振動型駆動装置の構成図である。It is a block diagram of the vibration type drive device of one Embodiment of this invention. 図１の駆動装置の周波数特性を示す図である。It is a figure which shows the frequency characteristic of the drive device of FIG. 図１の駆動装置の検出信号の関係を示す図である。It is a figure which shows the relationship of the detection signal of the drive device of FIG. 図１の駆動装置の判定基準を示す図である。It is a figure which shows the criterion of the drive device of FIG. 図１の駆動装置における移動体の走査駆動を示す図である。It is a figure which shows the scanning drive of the moving body in the drive device of FIG. 図１の駆動装置における移動体の位置決めを示す図である。It is a figure which shows the positioning of the moving body in the drive device of FIG.

これより、本発明の実施形態について、図面を参照しながら説明する。図１に、本発明の１つの実施形態の振動型駆動装置１の構成を示す。この振動型駆動装置１は、機械的構成要素であるアクチュエータ２と、アクチュエータ２に駆動電圧を印加する駆動回路３と、駆動回路３の出力する電圧と電流との位相差を検出する位相差検出回路（位相差検出手段）４と、位相差検出回路４が検出した位相差を考慮して駆動回路３を制御するマイコンからなる制御装置（判定手段）５とを有する。 Embodiments of the present invention will now be described with reference to the drawings. In FIG. 1, the structure of the vibration type drive device 1 of one embodiment of this invention is shown. This vibration type driving apparatus 1 includes an actuator 2 that is a mechanical component, a drive circuit 3 that applies a drive voltage to the actuator 2, and a phase difference detection that detects a phase difference between a voltage and a current output from the drive circuit 3. A circuit (phase difference detection means) 4 and a control device (determination means) 5 comprising a microcomputer for controlling the drive circuit 3 in consideration of the phase difference detected by the phase difference detection circuit 4 are provided.

アクチュエータ２は、一端が錘６に固定され、駆動電圧が印加されると伸縮する圧電素子（電気機械変換素子）７と、圧電素子７の伸縮によって軸方向に振動する軸状の駆動部材８と、駆動部材８に滑り移動可能に摩擦係合する移動体９と、駆動部材８の両端に設けられ、移動体９と当接して移動体９の移動を制限する規制部材１０，１１とを有する。 The actuator 2 has one end fixed to the weight 6 and expands and contracts when a drive voltage is applied, and an axial drive member 8 that vibrates in the axial direction due to expansion and contraction of the piezoelectric element 7. And a movable body 9 that frictionally engages the drive member 8 so as to be slidable, and regulating members 10 and 11 that are provided at both ends of the drive member 8 and that abut against the movable body 9 and restrict the movement of the movable body 9. .

駆動回路３は、制御装置５から入力される制御信号Ｓ１、Ｓ２，Ｓ３，Ｓ４によってそれぞれスイッチングされる４つのＦＥＴ１２，１３，１４，１５によって、圧電素子７の両電極を、直流電源１６に接続、または、接地するブリッジ回路である。 The drive circuit 3 connects both electrodes of the piezoelectric element 7 to the DC power supply 16 by four FETs 12, 13, 14, and 15 that are respectively switched by control signals S 1, S 2, S 3, and S 4 input from the control device 5. Or a grounded bridge circuit.

位相差検出回路４は、駆動回路３と圧電素子７との間の電路に設けたシャント抵抗１７の両端の電位差を出力する比較器１８と、比較器１８の出力を十分に大きなゲインで増幅してディジタル化する整形器１９と、整形器１９の出力信号とＦＥＴ１２に入力される制御信号Ｓ１との排他論理和（ＸＯＲ）を出力するＸＯＲ演算子２０と、ＸＯＲ演算子２０の出力の平均電圧を出力する整流器２１と、整流器２１の出力電圧をディジタル変換して制御装置５に入力するＡＤ変換器２２とかを有する。 The phase difference detection circuit 4 outputs a potential difference between both ends of a shunt resistor 17 provided in an electric path between the drive circuit 3 and the piezoelectric element 7 and amplifies the output of the comparator 18 with a sufficiently large gain. The digitizer 19, the XOR operator 20 that outputs the exclusive OR (XOR) of the output signal of the shaper 19 and the control signal S 1 input to the FET 12, and the average voltage of the output of the XOR operator 20 And an AD converter 22 that digitally converts the output voltage of the rectifier 21 and inputs the converted voltage to the control device 5.

シャント抵抗１７を圧電素子７側から駆動回路３側に電流が流れている場合、シャント抵抗１７の圧電素子７側の電位が高くなる。このため、比較器１８は、正の電圧を出力し、整形器１９は、制御用電源電圧（例えば５Ｖ）と等しい電圧を出力する。逆に、シャント抵抗１７を駆動回路３から圧電素子７に向かって電流が通過している場合は、シャント抵抗１７の圧電素子７側の電位が低くなるが、比較器１８は、負の値を出力できないので０Ｖを出力し、整形器１９の出力も０Ｖとなる。 When a current flows through the shunt resistor 17 from the piezoelectric element 7 side to the drive circuit 3 side, the potential of the shunt resistor 17 on the piezoelectric element 7 side becomes high. Therefore, the comparator 18 outputs a positive voltage, and the shaper 19 outputs a voltage equal to the control power supply voltage (for example, 5V). Conversely, when a current passes through the shunt resistor 17 from the drive circuit 3 toward the piezoelectric element 7, the potential of the shunt resistor 17 on the piezoelectric element 7 side is lowered, but the comparator 18 has a negative value. Since it cannot be output, 0V is output, and the output of the shaper 19 is also 0V.

つまり、整形器１９の出力は、圧電素子７を流れる電流がシャント抵抗１７を介して流出する正の位相であるときはＯＮ状態になり、圧電素子７を流れる電流がゼロまたはシャント抵抗１７から圧電素子７に電流が流れ込む負の位相であるときはＯＦＦ状態になる。 That is, the output of the shaper 19 is ON when the current flowing through the piezoelectric element 7 is in a positive phase that flows out through the shunt resistor 17, and the current flowing through the piezoelectric element 7 is zero or the piezoelectric current from the shunt resistor 17 is piezoelectric. In the negative phase where current flows into the element 7, the element 7 is turned off.

図２に、アクチュエータ２の駆動電圧に対する周波数特性を、移動体９が、駆動部材８の中央Ｐａにあるときと、圧電素子７側の規制部材１０に当接する位置（近位可動端）Ｐ１にあるときと、他端の規制部材１１に当接する位置（遠位可動端）Ｐ２にあるときとについて、それぞれ示す。Ａ図に示すように、移動体９が中央Ｐａにあるとき、駆動部材８の変位（振幅）は、駆動電圧が約５００ｋＨｚのときに共振して最大となる。しかしながら、移動体９が近位可動端Ｐ１または遠位可動端Ｐ２にあるときは、約３００ｋＨｚ程度で駆動部材８の変位が共振による最大値を示す。 FIG. 2 shows the frequency characteristics with respect to the driving voltage of the actuator 2 when the moving body 9 is at the center Pa of the driving member 8 and at the position (proximal movable end) P1 in contact with the regulating member 10 on the piezoelectric element 7 side. A case where it is present and a case where it is at a position (distal movable end) P2 in contact with the restriction member 11 at the other end will be described. As shown in FIG. A, when the moving body 9 is at the center Pa, the displacement (amplitude) of the drive member 8 resonates and becomes maximum when the drive voltage is about 500 kHz. However, when the moving body 9 is at the proximal movable end P1 or the distal movable end P2, the displacement of the drive member 8 shows a maximum value due to resonance at about 300 kHz.

これは、移動体９が規制部材１０，１１に当接すると、駆動部材８に対する滑りが規制され、移動体９が駆動部材８と一体に振動することになるため、圧電素子７の伸縮によって振動する駆動部材８の質量が、あたかも移動体９の質量分だけ増加したかのように振る舞うからである。したがって、移動体９が規制部材１０，１１に当接していなければ、移動体９が中央Ｐａからずれていても、駆動部材８の変位は、移動体９が中央Ｐａにあるときとほぼ同じ周波数特性を示す。 This is because, when the moving body 9 comes into contact with the regulating members 10 and 11, the sliding with respect to the driving member 8 is restricted, and the moving body 9 vibrates integrally with the driving member 8. This is because the mass of the driving member 8 to behave behaves as if the mass of the movable body 9 has increased. Therefore, if the moving body 9 is not in contact with the regulating members 10 and 11, even if the moving body 9 is displaced from the center Pa, the displacement of the drive member 8 is substantially the same frequency as when the moving body 9 is at the center Pa. Show properties.

さらに、Ｂ図に示すように、移動体９が中央Ｐａにあるときも可動端Ｐ１またはＰ２にあるときも、移動体９の変位が最大となる共振点において、圧電素子７を流れる電流の位相は、駆動電圧の位相と同位相となる。詳しく説明すると、圧電素子７は、低周波域では位相が進むキャパシタと同視することができ、容量性の特性を示すが、周波数が高くなると圧電素子７および駆動部材８の慣性力および弾性力による圧電素子７の伸縮に対する抵抗が、圧電素子７に流れる電流の抵抗となり、インダクタのように電流の位相を遅らせる作用を呈する。駆動部材８のゲインが最大となる共振点は、このキャパシタとインダクタとが打ち消し合う点であるから、圧電素子７の力率は１００％となり、その電流は駆動電圧と同位相となる。共振点よりも周波数が高くなると、インダクタの作用が強くなるため、電流が電圧に対して遅れる誘導性の特性を呈する。 Furthermore, as shown in FIG. B, the phase of the current flowing through the piezoelectric element 7 at the resonance point where the displacement of the moving body 9 is maximum, even when the moving body 9 is at the center Pa or at the movable end P1 or P2. Is in phase with the phase of the drive voltage. More specifically, the piezoelectric element 7 can be regarded as a capacitor whose phase is advanced in a low frequency range and exhibits a capacitive characteristic. However, as the frequency increases, the piezoelectric element 7 is driven by the inertial force and elastic force of the piezoelectric element 7 and the driving member 8. The resistance against expansion and contraction of the piezoelectric element 7 becomes the resistance of the current flowing through the piezoelectric element 7 and exhibits an action of delaying the phase of the current like an inductor. The resonance point at which the gain of the driving member 8 is maximized is a point where the capacitor and the inductor cancel each other. Therefore, the power factor of the piezoelectric element 7 is 100%, and the current is in phase with the driving voltage. When the frequency is higher than the resonance point, the action of the inductor becomes stronger, and thus an inductive characteristic in which the current is delayed with respect to the voltage is exhibited.

移動体９が規制部材１０，１１に当接しているか否かは、これらの周波数特性の違い、特に、圧電素子７を流れる電流の位相（駆動電圧との位相差）を検出することで確認可能である。図２からは、共振点において、電流の位相の変化率が最大となっており、移動体９の位置による電流の位相の変化が大きくなっていることが分かる。よって、駆動電圧の周波数が、移動体９が規制部材１０，１１に当接している時の共振点から、規制部材１０，１１から離間しているときの共振点までの間であれば、移動体９が可動端Ｐ１またはＰ２に到達したことによる位相の変化が大きく、検出し易い。さらに、アクチュエータ２では、移動体９が規制部材１０，１１に当接していない状態が通常の状態であるから、通常の検出値がゼロである方が都合がよい。 Whether or not the moving body 9 is in contact with the regulating members 10 and 11 can be confirmed by detecting the difference between these frequency characteristics, in particular, the phase of the current flowing through the piezoelectric element 7 (phase difference from the driving voltage). It is. From FIG. 2, it can be seen that the rate of change of the phase of the current is the maximum at the resonance point, and the change of the phase of the current due to the position of the moving body 9 is large. Therefore, if the frequency of the driving voltage is between the resonance point when the moving body 9 is in contact with the regulating members 10 and 11 and the resonance point when the moving body 9 is separated from the regulating members 10 and 11, the drive voltage moves. The change in phase due to the body 9 reaching the movable end P1 or P2 is large and easy to detect. Furthermore, in the actuator 2, since the state in which the moving body 9 is not in contact with the regulating members 10 and 11 is a normal state, it is more convenient that the normal detection value is zero.

図３に、駆動電圧の電圧と同位相の制御信号Ｓ１、圧電素子７の電流の位相を示す整形器１９の出力、ＸＯＲ演算子２０の出力および整流器２１の出力を示す。この図は、圧電素子７の電流の位相を検出するために、移動体９が中央Ｐａにあるときの共振周波数でデューティ比が５０％の矩形波を駆動電圧として入力する場合を示す。図において、左側は圧電素子７の力率が１００％である場合を示し、右側は、圧電素子７を流れる電流が、駆動電圧に対して遅れている場合を示す FIG. 3 shows the control signal S1 having the same phase as the voltage of the drive voltage, the output of the shaper 19 indicating the phase of the current of the piezoelectric element 7, the output of the XOR operator 20, and the output of the rectifier 21. This figure shows a case where a rectangular wave having a resonance frequency and a duty ratio of 50% is input as a drive voltage when the moving body 9 is at the center Pa in order to detect the phase of the current of the piezoelectric element 7. In the figure, the left side shows the case where the power factor of the piezoelectric element 7 is 100%, and the right side shows the case where the current flowing through the piezoelectric element 7 is delayed with respect to the drive voltage.

ＸＯＲ演算子２０の出力は、駆動電圧の位相と、圧電素子７の電流の位相とが食い違っているときだけＯＮとなる。つまり、ＸＯＲ演算子２０は、圧電素子７の電流の駆動電圧に対する位相差に反比例するデューティ比の矩形波を出力し、位相差が±１８０°で１００％のデューティ比となる。但し、図２に示されるように、位相差は、±９０°の範囲内でしか変動せず、ＸＯＲ演算子２０の出力のデューティ比の最大値は５０％である。整流器２１は、図４に示すように、ＸＯＲ演算子２０の出力電圧を平均化し、ＸＯＲ出力のデューティ比に比例した電圧の直流電圧、つまり、アナログ電圧信号を出力する。ここで、ＸＯＲ出力を平均化するため、電流の位相が駆動電圧に対して進んでいるか遅れているかの情報は失われる。 The output of the XOR operator 20 is turned on only when the phase of the driving voltage and the phase of the current of the piezoelectric element 7 are different. That is, the XOR operator 20 outputs a rectangular wave having a duty ratio that is inversely proportional to the phase difference of the current of the piezoelectric element 7 with respect to the drive voltage, and has a duty ratio of 100% when the phase difference is ± 180 °. However, as shown in FIG. 2, the phase difference fluctuates only within a range of ± 90 °, and the maximum value of the duty ratio of the output of the XOR operator 20 is 50%. As shown in FIG. 4, the rectifier 21 averages the output voltage of the XOR operator 20, and outputs a DC voltage that is proportional to the duty ratio of the XOR output, that is, an analog voltage signal. Here, in order to average the XOR output, information on whether the phase of the current is advanced or delayed with respect to the drive voltage is lost.

制御装置５は、整流器２１の電圧信号をディジタル変換した信号が入力され、この信号が、所定の値以上である場合、つまり、圧電素子７の電流の駆動電圧に対する位相差が所定の値以上、例えば３６°（ＸＯＲ出力で２Ｖ）以上であれば、移動体９が規制部材１０または１１に当接していると判断する（判定手段）。 The control device 5 receives a signal obtained by digitally converting the voltage signal of the rectifier 21, and when this signal is equal to or greater than a predetermined value, that is, the phase difference of the current of the piezoelectric element 7 with respect to the drive voltage is equal to or greater than a predetermined value. For example, when it is 36 ° (XOR output: 2V) or more, it is determined that the moving body 9 is in contact with the regulating member 10 or 11 (determination means).

振動型駆動装置１において、駆動部材８のゲインの共振周波数の約７０％の周波数でデューティ比約３０％または約７０％程度の矩形波状の駆動電圧を圧電素子７に印加すれば、移動体９を駆動部材８に対して効率よく移動させられる。よって、制御装置５は、駆動回路３に、移動体９を遠位可動端Ｐ２（規制部材１１）に向かって移動させるときは、周波数３５０ｋＨｚ、デューティ比３０％の前進駆動電圧を出力させ、移動体９を近位可動端Ｐ１（規制部材１０）に向かって移動させるときは、周波数３５０ｋＨｚ、デューティ比７０％の後進駆動電圧を出力させ、移動部材９が可動端Ｐ１またはＰ２にあるかどうかを検出するときは、駆動回路に、周波数５００ｋＨｚ、デューティ比５０％の検出駆動電圧を出力させる。 In the vibration type driving apparatus 1, if a rectangular wave driving voltage having a duty ratio of about 30% or about 70% is applied to the piezoelectric element 7 at a frequency of about 70% of the resonance frequency of the gain of the driving member 8, the moving body 9 Can be efficiently moved relative to the drive member 8. Therefore, the control device 5 causes the drive circuit 3 to output a forward drive voltage with a frequency of 350 kHz and a duty ratio of 30% when moving the moving body 9 toward the distal movable end P2 (the regulating member 11). When the body 9 is moved toward the proximal movable end P1 (the restricting member 10), a reverse drive voltage with a frequency of 350 kHz and a duty ratio of 70% is output, and whether the moving member 9 is at the movable end P1 or P2 is determined. When detecting, the drive circuit is caused to output a detection drive voltage having a frequency of 500 kHz and a duty ratio of 50%.

本実施形態の駆動装置１をＸ−Ｙ方向に２つ用いて光学部材を位置決め可能とし、光学部材を走査移動させて、光学出力が得られる位置を探索する場合、所定のパルス数の前進駆動電圧または後進駆動電圧を出力して、光学部材を保持する移動体９を１走査ピッチ分だけ移動させる度に、光学出力があるかどうかを確認することになる。この光学出力の確認を行う間は、移動体９の移動を停止しているので、この間に、検出駆動電圧を出力して、移動体９が可動端Ｐ１またはＰ２に達したかどうかを確認するとよい。 When the optical device can be positioned by using two drive devices 1 of the present embodiment in the X and Y directions, and the optical member is scanned to search for a position where an optical output can be obtained, a forward drive of a predetermined number of pulses is performed. Every time the movable body 9 holding the optical member is moved by one scanning pitch by outputting a voltage or a reverse drive voltage, it is confirmed whether or not there is an optical output. Since the movement of the moving body 9 is stopped during the confirmation of the optical output, the detection drive voltage is output during this time to check whether the moving body 9 has reached the movable end P1 or P2. Good.

これにより、図５に示すように、従来は、移動体９の変位量の誤差を考慮して、可動端Ｐ１またはＰ２に当接してからさらに同じ方向にピッチ送りするような駆動をおこなっていたものが、移動体９が可動端Ｐ１，Ｐ２に達して直ぐに副走査方向に１ピッチ移動して次の走査を開始できるようになった。これにより、従来副走査方向の可動端に達する度に蓄積されていた遅れが解消され、素早い走査ができるようになった。 As a result, as shown in FIG. 5, conventionally, in consideration of an error in the displacement amount of the moving body 9, driving is performed such that the contact is made with the movable end P 1 or P 2 and then the pitch is further fed in the same direction. As soon as the movable body 9 reaches the movable ends P1 and P2, the moving body 9 can move one pitch in the sub-scanning direction and start the next scanning. As a result, the delay that has been accumulated every time the movable end in the sub-scanning direction is reached is eliminated, and quick scanning can be performed.

尚、本実施形態において、駆動回路３が検出駆動電圧を出力する場合、直流電源１６の電圧を低下させるようにしてもよい。検出駆動電圧は、移動部材９の位置を確認するためだけのものであるので、駆動トルクが小さくてもよく、電圧を低くすることで、消費電力を節減することができる。但し、電圧を低くしすぎると移動体９が駆動部材８上で滑り変位しないため、可動部材８の見かけ上の質量が大きくなり、移動体９が可動端Ｐ１，Ｐ２になくても共振点が低下してしまうため、移動体９の位置を確認できなくなるので注意が必要である。 In the present embodiment, when the drive circuit 3 outputs the detection drive voltage, the voltage of the DC power supply 16 may be lowered. Since the detected drive voltage is only for confirming the position of the moving member 9, the drive torque may be small, and power consumption can be reduced by reducing the voltage. However, if the voltage is too low, the moving body 9 will not slide and displace on the drive member 8, so the apparent mass of the movable member 8 will increase, and the resonance point will be present even if the moving body 9 is not at the movable ends P1, P2. Since it falls, it becomes impossible to confirm the position of the moving body 9, and it needs attention.

また、本実施形態において、図２に示すように、前進駆動電圧および後進駆動電圧の基本周波数３５０ｋＨｚにおいても、圧電素子７の電流の位相から、移動体９が可動端Ｐ１，Ｐ２にあるかどうかを確認できる。つまり、前進駆動電圧または後進駆動電圧を印加して移動体９を移動させながら、圧電素子７の電流の駆動電圧に対する位相差を検出してもよい。 Further, in this embodiment, as shown in FIG. 2, whether or not the moving body 9 is at the movable ends P1 and P2 from the phase of the current of the piezoelectric element 7 even at the basic frequency of 350 kHz of the forward drive voltage and the reverse drive voltage. Can be confirmed. That is, the phase difference of the current of the piezoelectric element 7 with respect to the drive voltage may be detected while moving the moving body 9 by applying the forward drive voltage or the reverse drive voltage.

図６に示すように、移動体９を可動端Ｐ１，Ｐ２のいずれかに原点復帰させてから目標位置まで移動させる必要がある場合、前進駆動電圧または後進駆動電圧と圧電素子７の電流との位相差を検出して、原点復帰を検出することで、移動体９を目標位置まで移動させるのにようする時間を大幅に短縮できる。 As shown in FIG. 6, when it is necessary to move the moving body 9 to the target position after returning the origin to one of the movable ends P1 and P2, the forward drive voltage or the reverse drive voltage and the current of the piezoelectric element 7 are By detecting the phase difference and detecting the return to origin, the time required to move the moving body 9 to the target position can be greatly shortened.

但し、前進駆動電圧および後進駆動電圧は、デューティ比が３０％または７０％であるので、デューティ比５０％の矩形波に比べて高調波成分が多いため、検出できる電流の位相変化が小さくなるため、位相差検出回路４の分解能を高く設計する必要がある。 However, since the forward drive voltage and the reverse drive voltage have a duty ratio of 30% or 70%, there are more harmonic components than a rectangular wave with a duty ratio of 50%, so that the phase change of the detectable current is small. It is necessary to design the resolution of the phase difference detection circuit 4 high.

尚、図２に示したような周波数特性の変化は、アクチュエータ２の構成、特に、質量バランスに依存するので、移動体９が規制部材１０または１１に当接していると判断するＸＯＲ出力の閾値は、アクチュエータ毎に検討する必要がある。 The change in frequency characteristics as shown in FIG. 2 depends on the configuration of the actuator 2, particularly on the mass balance, so that the threshold of the XOR output for determining that the moving body 9 is in contact with the regulating member 10 or 11 Needs to be considered for each actuator.

１…振動型駆動装置
２…アクチュエータ
３…駆動回路
４…位相差検出回路
５…制御装置（判定手段）
７…圧電素子（電気機械変換素子）
８…駆動部材
９…移動体
１０，１１…規制部材
１６…直流電源
１７…シャント抵抗
１８…比較器
１９…整形器
２０…ＸＯＲ演算子
２１…整流器
２２…ＡＤ変換器 DESCRIPTION OF SYMBOLS 1 ... Vibration type drive device 2 ... Actuator 3 ... Drive circuit 4 ... Phase difference detection circuit 5 ... Control apparatus (determination means)
7 ... Piezoelectric element (electromechanical transducer)
DESCRIPTION OF SYMBOLS 8 ... Drive member 9 ... Moving body 10, 11 ... Restriction member 16 ... DC power supply 17 ... Shunt resistance 18 ... Comparator 19 ... Shaper 20 ... XOR operator 21 ... Rectifier 22 ... AD converter

Claims

電気機械変換素子と、
電気機械変換素子によって振動させられる駆動部材と、
前記駆動部材に摩擦係合する移動体と、
前記移動体と当接して前記移動体の相対移動を制限し得る規制部材と、
前記電気機械変換素子に周期的な駆動電圧を印加する駆動回路と、
前記駆動電圧と、前記電気機械変換素子を流れる電流との位相差を検出する位相差検出手段と、
前記位相差が所定の範囲にあるとき、前記移動体が前記規制部材に当接していると判断する判定手段とを有することを特徴とする振動型駆動装置。 An electromechanical transducer,
A drive member that is vibrated by an electromechanical transducer;
A moving body frictionally engaged with the drive member;
A regulating member that abuts on the moving body to limit relative movement of the moving body;
A drive circuit for applying a periodic drive voltage to the electromechanical transducer;
A phase difference detecting means for detecting a phase difference between the drive voltage and a current flowing through the electromechanical transducer;
A vibration type driving apparatus comprising: a determination unit that determines that the moving body is in contact with the restriction member when the phase difference is in a predetermined range.

前記駆動回路は、前記位相差を検出する際、前記駆動電圧の周波数を、前記移動体が前記規制部材に当接していない状態で前記駆動部材の変位が最大となる共振周波数とすることを特徴とする請求項１に記載の振動型駆動装置。 The drive circuit, when detecting the phase difference, sets the frequency of the drive voltage to a resonance frequency at which the displacement of the drive member is maximum when the moving body is not in contact with the regulating member. The vibration type driving device according to claim 1.

前記駆動回路は、前記位相差を検出する際、前記駆動電圧をデューティ比５０％の矩形波電圧とし、
前記判定手段は、前記駆動電圧に対する前記電流の位相の遅れが所定の値以上になったとき、前記移動体が前記規制部材に当接していると判断することを特徴とする請求項２に記載の振動型駆動装置。 When the drive circuit detects the phase difference, the drive voltage is a rectangular wave voltage with a duty ratio of 50%,
3. The determination unit according to claim 2, wherein the determination unit determines that the moving body is in contact with the restriction member when a delay of the phase of the current with respect to the drive voltage becomes a predetermined value or more. Vibration type drive device.

前記駆動回路は、前記位相差を検出する際、駆動電圧の波高を低くすることを特徴とする請求項１から３のいずれかに記載の振動型駆動装置。 4. The vibration type driving device according to claim 1, wherein when the phase difference is detected, the driving circuit lowers a wave height of the driving voltage. 5.

電気機械変換素子と、電気機械変換素子によって振動させられる駆動部材と、前記駆動部材に摩擦係合する移動体と、前記移動体と当接して前記移動体の移動を制限し得る規制部材とを有する振動型駆動装置の制御方法であって、
前記電気機械変換素子に印加する駆動電圧と、前記電気機械変換素子を流れる電流との位相差が所定の範囲にあるとき、前記移動体が前記規制部材に当接していると判断することを特徴とする振動型駆動装置の制御方法。 An electromechanical conversion element; a drive member that is vibrated by the electromechanical conversion element; a movable body that frictionally engages the drive member; and a regulating member that abuts the movable body and can limit the movement of the movable body. A control method of a vibration type driving device having,
When the phase difference between the drive voltage applied to the electromechanical transducer and the current flowing through the electromechanical transducer is within a predetermined range, it is determined that the moving body is in contact with the regulating member. A control method of the vibration type driving device.

前記位相差の検出は、前記移動体を移動させる必要がないときに、前記駆動電圧の波形を、前記移動体を移動させるときと異ならせて行うことを特徴とする請求項５に記載の振動型駆動装置の制御方法。 6. The vibration according to claim 5, wherein the detection of the phase difference is performed by making the waveform of the driving voltage different from that when the moving body is moved when the moving body does not need to be moved. Method for controlling mold drive device.

前記位相差を検出するときは、デューティ比５０％で、前記移動体が前記規制部材に当接していない状態で前記駆動部材の変位が最大となる共振周波数の駆動電圧を記電気機械変換素子に印加し、前記駆動電圧に対する前記電流の位相の遅れが所定の値以上になったとき、前記移動体が前記規制部材に当接していると判断することを特徴とする請求項６に記載の振動型駆動装置の制御方法。 When the phase difference is detected, a drive voltage having a resonance frequency at which the displacement of the drive member is maximum when the moving body is not in contact with the restriction member at a duty ratio of 50% is recorded on the electromechanical transducer. The vibration according to claim 6, wherein when the phase difference of the current with respect to the driving voltage is greater than or equal to a predetermined value, it is determined that the moving body is in contact with the regulating member. Method for controlling mold drive device.

前記移動体の移動を停止する度に、前記位相差を検出することを特徴とする請求項５から７のいずれかに記載の振動型駆動装置の制御方法。 8. The method of controlling a vibration type driving device according to claim 5, wherein the phase difference is detected every time the movement of the moving body is stopped.