JP5484522B2 - Vibration wave drive - Google Patents

Description

  The present invention relates to a vibration wave drive device such as a vibration wave motor having a vibrator having an electric / mechanical energy conversion element as a drive source.

  In general, a vibration wave driving device such as a vibration wave motor has a vibrator that forms driving vibration and a rotating body that is in pressure contact with the vibrator, and the vibrator and the rotating body are moved by the driving vibration. It is made to move relatively.

  Conventionally, as an example of a vibration wave driving device such as a vibration wave motor that has a ring type vibrator and can be driven with multiple degrees of freedom, there is one disclosed in Patent Document 1, for example. This multi-degree-of-freedom vibration wave motor combines multi-plane vibration and in-plane vibration as shown in FIGS. 16 (a) and 16 (b) to excite a single vibrator, thereby driving in multiple axes. It is possible.

JP 2003-116289 A

  In order to maintain a stable contact state between the contact portion on the vibrator and the rotating body at all times, the number of contact portions on the vibrator with the rotating body that is a driven body having a spherical surface is three points, and It is known that the contact portions are preferably arranged at equal intervals so as to obtain a substantially uniform contact surface pressure. However, the conventional vibrator has a problem that the operating range is limited, so that the number of contact portions is four or more.

  In the case of a 4-point contact part, the contact between each contact part and the rotating body changes from time to time due to the difference in the wear progressing speed of each contact part, and a stable contact state can always be maintained over a long period of time. Have difficulty. And since the motor control parameter for every contact state of a time calendar changes greatly, it is disadvantageous also in achieving high durability in terms of control.

  Further, in the conventional vibration wave driving device, the contact portion on the vibrator has to be accurately arranged at the antinode vibration or in-plane vibration antinode used for driving. This is because displacement of the tip of the contact portion in the circumferential direction of the vibrator occurs due to deviation from the antinode position, and unnecessary feeding motion occurs. Furthermore, due to uneven rigidity in the circumferential direction of the vibrator, which is unavoidable when manufacturing the vibrator, the spatial position phase of the anti-plane vibration and in-plane vibration used for driving is shifted, and unnecessary feed movement occurs. In some cases, it was difficult to manufacture the vibrator as expected. In consideration of future mass productivity, there is a need for a vibration wave driving device and a control device that do not cause any problems even if such problems occur.

  Further, in the vibration wave driving device including the vibrator having a plurality of contact portions with the rotating body, it is difficult to rotate the rotating body around an arbitrary axis.

  An object of the present invention is to provide a vibration wave driving device including a vibrator having a plurality of contact portions with a rotating body, which can rotate the rotating body around an arbitrary axis.

  In order to achieve the above object, a vibration wave driving device of the present invention includes a vibrator having a plurality of contact portions with a rotating body, and the vibrator generates a first standing wave in the vibrator. A first electrode group to which one driving signal is supplied, a second driving signal for generating at least two standing waves that are combined to generate a second standing wave in the vibrator, and a third A second electrode group and a third electrode group to which a drive signal is supplied, respectively, wherein the second standing wave has an anti-node spatial position phase, the second drive signal and Set by a third drive signal, the first standing wave is an in-plane vibration standing wave and the second standing wave is an out-of-plane vibration standing wave, or the first standing wave is out-of-plane The vibration standing wave and the second standing wave are in-plane vibration standing waves, and the plurality of contact portions are integral multiples of 1/2 of the wavelength of the first standing wave. They are arranged at intervals.

  ADVANTAGE OF THE INVENTION According to this invention, in the vibration wave drive device provided with the vibrator | oscillator which has multiple contact parts with a rotary body, the vibration wave drive device which can rotate a rotary body around arbitrary axes | shafts can be provided.

It is a perspective view which shows the ring type vibrator | oscillator of the vibration wave motor used for embodiment. It is explanatory drawing of the rotating shaft in the drive around arbitrary axes. It is a schematic diagram which shows the order of the drive vibration generated in a vibrator | oscillator, and its spatial position phase. It is explanatory drawing of driving force transmission. It is an electrode pattern figure of a piezoelectric element. It is a figure which shows the example which deform | transformed the rotation standing wave. It is a block diagram which shows the structure of the control apparatus of the vibration wave drive device based on 1st Embodiment. It is a vibrator drive state figure explaining a motion of a contact part by drive vibration. It is a vibrator drive state figure explaining the circumferential direction displacement by a rotation standing wave. It is explanatory drawing explaining the unnecessary circumferential direction displacement. It is explanatory drawing of the behavior of the contact part by a fixed standing wave. It is a block diagram which shows the structure of the control apparatus of the vibration wave drive device based on 2nd Embodiment. It is a graph which shows the amplitude distribution of the traveling wave by two standing waves. It is a block diagram which shows the structure of the control apparatus of the vibration wave drive device based on 3rd Embodiment. It is a block diagram which shows the structure of the control apparatus of the vibration wave drive device based on the modification of 3rd Embodiment. It is a figure which shows an example of an out-of-plane vibration and an in-plane vibration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
<Structure of vibrator>
First, the vibrator of the vibration wave motor according to the present embodiment will be described.

  FIG. 1 is a perspective view showing a ring type vibrator of a vibration wave motor used in the present embodiment.

  This ring type vibrator 4 has a piezoelectric element 2 as an electrical / mechanical energy conversion element. An elastic body 1 made of a metal material or the like is fixed to the upper portion of the piezoelectric element 2. On the surface of the elastic body 1, three contact portions 3a, 3b, 3c having protrusions are formed.

  A rotating body (not shown) having a spherical surface serving as a contact surface is brought into pressure contact with the contact portions 3a, 3b, 3c from the Z-axis direction in FIG. In the elliptical motion formed at the tips of the contact portions 3a, 3b, and 3c, the driving force is transmitted to the rotating body by the frictional force due to the pressure contact.

<Driving principle>
(A) Principle of Elliptical Motion Formed at Tip of Contact Part Next, the principle of elliptical motion formed at the tip of the contact parts 3a, 3b, 3c will be described with reference to FIG. FIG. 2 is an explanatory diagram of a rotating shaft in driving around an arbitrary axis.

  When an AC voltage is applied to the piezoelectric element 2 in FIG. 1, the element 2 expands and contracts in the circumferential direction, and the entire vibrator excites odd-order or even-order drive vibration as shown in FIG. 16 (a) or (b). To do. At this time, the displacement of the vibration can be expanded by bringing the frequency of the AC voltage close to the natural frequency of the vibrator 4. When the antinodes of the vibration and the spatial position phases of the contact portions 3a, 3b, 3c are matched, for example, the tips of the contact portions 3a, 3b, 3c are moved in the out-of-plane direction of the vibrator 4 by the vibration of FIG. A displacement in the Z-axis direction of FIG. 1 is generated.

  Further, due to the vibration shown in FIG. 16B, the tips of the contact portions 3a, 3b, 3c are displaced in the in-plane direction of the vibrator 4, that is, in the radial direction in the ring shown in FIG. If the natural frequencies of the two drive vibrations in the vibrator 4 are substantially matched, both drive vibrations can be generated at the same frequency at the same time. Furthermore, an elliptical motion can be generated at the tips of the contact portions 3a, 3b, 3c by giving a temporal phase difference to both drive vibrations.

  Here, in the multi-degree-of-freedom drive that can be driven around an arbitrary axis, two terms of tilt rotation and horizontal rotation are defined by the rotation axis of the rotating body. When the rotator is a sphere as shown in FIG. 2, the rotation in the tilt direction having the rotation axis in the plane including the rotation center of the rotator and having the center axis of the vibrator 4 as a normal vector, that is, φ = When the angle is 0 degrees (θ = 0 to 360 degrees), the rotation is inclined.

  Further, the horizontal rotation with the central axis of the vibrator 4 as the rotation axis, that is, when φ = ± 90 degrees is set as the horizontal rotation. In the case of driving around an arbitrary axis where φ ≠ 0 and φ ≠ ± 90 as shown in FIG. 2, it is considered as a rotation in which a tilt rotation component and a horizontal rotation component are combined. Since the horizontal rotation will be described later, only the tilt rotation will be described in the following description.

(B) Principle of Rotating Body Driving Next, by combining the driving vibrations shown in FIGS. 16A and 16B, elliptical motion is formed at the tips of the contact portions 3a, 3b, and 3c to drive the rotating body. The principle will be described with reference to FIGS.

  FIG. 3 is a schematic diagram showing the order (wave number) of driving vibration generated in the vibrator 4 and its spatial position phase. 4A and 4B are explanatory views of driving force transmission.

  In FIG. 3, solid line portions 9a to 9e and broken line portions 10a to 10e extending in the radial direction indicate antinodes of vibration, and the vibration phases are reversed between the solid line portions 9a to 9e and the broken line portions 10a to 10e.

  In FIG. 3, the outer circle indicated by reference numeral 5 represents three out-of-plane vibrations, and the inner circle indicated by reference numeral 6 represents two in-plane vibrations. Further, the deformation of the vibrator 4 due to in-plane vibration is indicated by an ellipse 11 on the inner peripheral side of the inner circle 6 in an easily understandable manner. Further, there are three contact portions 3a to 3c at equal intervals (120 degree intervals) at positions indicated by black circles in FIG.

  The contact portions 3a to 3c exist at antinodes (solid lines 9a to 9c) of out-of-plane vibration, and the phases are the same. On the other hand, with respect to in-plane vibration, the contact portion 3a is at the position of the antinode (solid lines 9a, 9e), and the contact portions 3b, 3c are at a position shifted by 30 degrees from the antinode (broken lines 10d, 10e). And since the phase relationship in the in-plane vibration of contact part 3a, 3b, 3c is reverse, the displacement generation direction is reverse.

  At this time, if a phase difference (in this case, the in-plane vibration is delayed by 90 degrees) is applied between the in-plane vibration and the out-of-plane vibration to excite both vibrations, the contact portion 3a has the arrow W1 in FIG. Generate the elliptic motion shown. Moreover, the contact parts 3b and 3c generate | occur | produce the elliptical motion which the arrow W2 of FIG.4 (b) shows. However, FIGS. 4A and 4B are observed from the viewpoints A, B, and C in FIG. As a result, the contact portion 3a generates a feed movement that lifts the rotating body 13, and the driving force is transmitted to the rotating body 13 in the direction of the arrow W3 in FIG. Since the rotation axis by the feed movement of the contact portion becomes a straight line perpendicular to the straight line connecting the contact portion and the center of the ring, this feed movement causes the rotating body 13 to rotate about the X axis of FIG. To do. Further, the contact portions 3b and 3c generate a feed movement that retracts the rotating body 13 as indicated by an arrow W4 in FIG. 4B, and the contact portions 3b and 3c are respectively connected to the straight lines 7 and 7 in FIG. A driving force having 8 as a rotation axis is transmitted to the rotating body 13.

  Since the contact portions 3b and 3c are located at the same angle away from the antinodes of the in-plane vibration, it can be considered that the radial amplitudes due to the in-plane vibration are equal and the driving forces are substantially the same. Therefore, if the components that are canceled out by adding both driving forces are removed, the remaining driving force is the driving force with the X axis in FIG. 3 as the rotation axis corresponding to the bisector of the angle formed by the straight lines 7 and 8. Become. Therefore, the feed movement of the three contact portions 3a to 3c is a feed movement that realizes an inclined rotation with the X axis as the rotation axis when combined.

  In principle, this embodiment has any order of even-order in-plane direction and odd-order out-of-plane drive vibration, or odd-order in-plane direction and even-order out-of-plane drive vibration. It is also possible to combine vibration modes. Therefore, the present invention is not limited to the combination of the out-of-plane tertiary vibration of FIG. 16A and the in-plane secondary vibration of FIG. As a specific example, the combination of FIGS. 16A and 16B is used in the following description.

<Control device according to the first embodiment>
Based on the basic drive principle described above, the tilt rotation drive control device according to the first embodiment of the present invention will be described in detail below.

(A) Piezoelectric Element and Vibration First, the piezoelectric element 2 used in the vibrator 4 and the vibration generated by the piezoelectric element 2 will be described with reference to FIGS.

  FIG. 5 is an electrode pattern diagram of the piezoelectric element 2 when viewed from the surface of the vibrator 4 opposite to the contact portions 3a to 3c. FIG. 6 is a diagram illustrating an example in which the rotating standing wave is modified.

  As shown in FIG. 5, the piezoelectric element 2 has two rows of electrodes arranged concentrically. In this embodiment, the inner circumferential side is an electrode group for in-plane vibration and the outer circumferential side is an electrode group for out-of-plane vibration. The positional phase relationship between the inner and outer electrode groups is not particularly determined but arbitrary. In addition, the surface (back side of FIG. 5) fixed to the elastic body 1 in the piezoelectric element 2 is a common electrode. At this time, the + symbol and the − symbol of the electrode indicate the polarization direction when the input signal having the same phase is applied to the electrode group of the same alphabet symbol and driven. For example, if a sine wave input signal having the same phase is input to all the F electrode groups, the piezoelectric elements in the F + electrode and F− electrode regions are deformed in opposite phases. If the F + electrode is a mountain, the F- electrode becomes a valley. Then, the standing wave of the out-of-plane tertiary vibration by the F electrode group is hereinafter referred to as a fixed standing wave (first standing wave by one vibration drive).

  Further, as shown in FIG. 5, the positions of the three contact portions 3 a to 3 c are arranged so as to overlap with the position of the F electrode group that generates the fixed standing wave. The R1 electrode group and the R2 electrode group are alternately arranged at positions shifted in the circumferential direction by 45 degrees in the spatial position phase, and in the same manner as the F electrode group, the in-plane secondary vibration having antinodes at the electrode positions is defined. Excited standing waves. At this time, vibration waveforms generated in the R1 electrode group and the R2 electrode group at a certain time are represented by the following equations. However, θ refers to FIG. 5, and Ar1 and Ar2 are amplitudes of the standing waves in the R1 electrode group and the R2 electrode group, respectively, and the amplitude is not zero.

fr1 (θ) = Ar1 · cos2θ
fr2 (θ) = Ar2 · cos2 (θ−45 °)
At this time, when two standing waves are vibrated in the same phase, a new combined standing wave is generated. The antinode has a position phase different from the original antinode position in the two standing waves. For example, when the amplitude ratio of the two in-plane secondary vibrations is 1: 1, the broken line 31 in FIG. 6 is deformed (antinode position θm = 22.5 degrees), the amplitude ratio is the same and the phases are reversed and synthesized. Then, the deformation of the dotted line 32 in FIG. 6 (antinode position θm = 67.5 degrees) is obtained. Θm is the position phase of the peak of the in-plane secondary vibration. The synthesized standing wave waveform is expressed by the following equation.

f (θ) = fr1 (θ) + fr2 (θ)
If the amplitude ratio of R1 standing wave and R2 standing wave is Ar = Ar2 / Ar1,
f ′ (θ) = − 2Ar1 (sin 2θ + Ar · sin 2 (θ−45 °))
And since f ′ (θ) = 0, the position phase of the antinode of the synthetic standing wave is
θm = 1/2 · arctanAr (provided that two standing waves have the same phase and 0 <θm <45 °).

  From the above formula, the antinode position phase θm is determined by the amplitude ratio Ar of both standing waves constituting the combined standing wave. Therefore, when the spatial position phase (antinode position) of the synthetic standing wave (in-plane vibration) is given as a command value, the amplitude ratio Ar = Ar2 / Ar1 is uniquely determined. Further, when the amplitude ratio Ar is determined, the amplitude f (θm) of the antinode position of the combined standing wave can be expressed as a function of Ar1, and therefore, both standing wave amplitudes Ar1 and Ar2 are determined based on the combined standing wave amplitude command value. . When 45 ° <θm <90 °, the composite standing wave is generated by inverting the phase of the R1 standing wave and adding them.

  From the above, it is possible to generate a standing wave of in-plane secondary vibration that can have an antinode in any spatial position phase. And this synthetic | combination standing wave is hereafter called a rotation standing wave (the 2nd standing wave by the other vibration drive).

<Configuration of Control Device According to First Embodiment>
FIG. 7 is a block diagram showing the configuration of the control device for the vibration wave driving device according to the first embodiment of the present invention.

  This control device controls the operation of the vibration wave motor 130 (vibration wave drive device), and includes a rotating standing wave generation unit 110 and a fixed standing wave generation unit 120.

  When the rotation axis and the number of rotations are given as the target values for the tilt rotation, a fixed standing wave (out-of-plane vibration) and a rotating standing wave (in-plane vibration) are obtained from the characteristics of the vibration wave motor 130 obtained in advance. The amplitude / phase difference and the spatial position phase of the rotating standing wave (in-plane vibration) are determined. These command values are sent to the rotating standing wave generator 110 and the fixed standing wave generator 120.

  The function of the rotating standing wave generator 110 will be described. First, from the command value of the spatial position phase of the given rotating standing wave, the phase of the two in-plane vibration standing waves constituting the rotating standing wave is selected to be the same or opposite, and the amplitude The ratio is calculated by the amplitude ratio calculator 111. Then, both voltage amplitudes are determined by the voltage amplitude determination unit 112 in accordance with the amplitude command value, and the input voltage amplitude Avr1 for the R1 electrode group and the input voltage amplitude Avr2 for the R2 electrode group are determined as the signal generation unit 113 and the signal generation unit. 114 respectively. Then, both signal generators 113 and 114 generate drive signals in accordance with the obtained commands and perform transmission in accordance with a phase difference command with respect to the fixed standing wave.

  Note that the number of standing waves constituting the rotating standing wave is not limited to two as in the present embodiment. Even when three or more rotating standing wave electrode groups are arranged in order to improve vibration generation efficiency, a signal may be input in the same way.

  On the other hand, in the fixed standing wave generation unit 120, the voltage amplitude determination unit 121 determines the input voltage amplitude from the amplitude command value of the fixed standing wave, and the signal generation unit 122 for the F electrode group generates and transmits a drive signal. Done.

  In this way, the signal generators 113, 114, 122 generate drive signals for generating each standing wave. Drive signals from the signal generators 113, 114, and 122 are supplied to the R1 electrode group, the R2 electrode group, and the F electrode group (see FIG. 5) in the vibration wave motor 130 through the power feeding unit, respectively, and the tilt rotation is driven. Is done.

<Change of rotation axis of tilt rotation>
Next, the change of the rotation axis of the tilt rotation due to the change of the spatial position phase of the rotating standing wave will be described with reference to FIGS.

  FIGS. 8A, 8B, and 8C are vibrator drive state diagrams for explaining the movement of the contact portions 3a to 3c due to drive vibration. FIG. 9 is a vibrator drive state diagram illustrating circumferential displacement due to a rotating standing wave.

  In FIG. 8, a plurality of contact portions 3 a to 3 c arranged in a plurality at equal intervals generate displacements in the out-of-plane direction (perpendicular to the plane of the drawing) with the same phase due to fixed standing waves that are out-of-plane tertiary vibrations. . Deformation of the rotating standing wave (in-plane secondary vibration) excited with a certain phase difference with respect to the fixed standing wave is indicated by solid-line ellipses 31 to 33. Further, the displacement directions of the three contact portions 3a to 3c due to in-plane deformation (in particular, only the radial direction here, and the circumferential direction will be described later) are indicated by arrows 3a-1 to 3c-1. At this time, if the in-plane vibration is delayed by, for example, 90 degrees in phase with respect to the out-of-plane vibration, the three contact portions 3a to 3c individually draw elliptical orbits and transmit the driving force to the rotating body.

  Although it is the same thing as the content demonstrated above, since the rotating shaft by the feed movement of contact part 3a-3c becomes a straight line which makes a right angle with the straight line which respectively connects a contact part and a ring center, in FIG. The rotation axes by the feed movement of the contact portions 3a to 3c are straight lines 20, 21, and 22, respectively. The positions of the contact part 3a and the contact part 3b are both shifted by 30 degrees from the antinode position of the rotating standing wave. Therefore, it can be considered that the generated driving forces are substantially the same, and the rotation axis by the two driving forces is a straight line 22 that is a bisector of the straight lines 20 and 21, and in total, an inclined rotation with the straight line 22 as the rotation axis is generated. To do.

  FIG. 9 shows the circumferential displacement actually occurring in addition to the radial displacements 3a-1 to 3c-1 of the contact portions 3a to 3c shown in FIG. It was added in 2. In the above description, only the radial displacement that affects the driving force of tilt rotation is considered, but in reality, both radial and circumferential displacements are generated simultaneously by in-plane secondary vibration, The tips of the contact portions 3a to 3c vibrate in the direction of the vector.

  At this time, the displacement in the circumferential direction does not occur in the contact part 3c where the antinode of the rotating standing wave coincides with the spatial position phase. The two contact portions 3a and 3b at other positions generate displacements 3a-1 and 3b-2 in a direction toward the top of the peak of the in-plane secondary vibration as shown in FIG. When the spatial position phase of the antinode in the in-plane secondary vibration and one contact part coincides, the positions of the remaining two contact parts are both shifted by 60 degrees from the peak of the same mountain. The amount of displacement in the circumferential direction is equal. Therefore, the driving force due to the circumferential displacement amount is canceled out and can be ignored.

  When the antinode of the rotating standing wave exists at a position rotated by 30 degrees from FIG. 8A as shown in FIG. 8B and FIG. 8C, the rotational axis is based on the same idea as FIG. 8A. They are straight lines 20 and 21, respectively. Therefore, as indicated by arrows W5 and W6 in FIG. 8C, when the position of the antinode of the rotating standing wave that is the in-plane secondary vibration is rotated by 60 degrees, the rotation axis of the inclined rotation is moved by 120 degrees (FIG. 8). (C) arrow W7). Further, the rotating standing wave can rotate 180 degrees. That is, as described with reference to FIG. 5 above, the rotating standing wave can be rotated by 0 to 90 degrees, and 90 to 180 degrees can be set based on the phase difference from the fixed standing wave. Thereby, the rotation axis of the tilt rotation is variable by 360 degrees.

  From the above, it is possible to control the position of the rotation axis of the tilt rotation by rotating the spatial position phase of the rotating standing wave in the plane.

<Advantages according to the present embodiment>
By using the control device according to the present embodiment, it is possible to drive with three contact portions arranged at equal intervals, so that a stable contact state with a substantially uniform contact surface pressure is maintained over a long period of time. Can be maintained. Thereby, the multi-degree-of-freedom drive control of the vibration wave motor is simplified, which is advantageous in achieving high durability.

  In addition, in the method of the present embodiment, unnecessary feed movement caused by mechanical causes can be canceled by an electrical drive signal from the control device, so that the vibrator can be manufactured easily and produced. Can increase the sex. As a result, it is possible to design with reduced processing accuracy and assembly accuracy of each component, and it is possible to improve mass productivity and reduce costs.

[Second Embodiment]
In the first embodiment, only the case where the antinodes of the in-plane secondary vibration and the spatial position phase of one contact portion coincide is considered. However, as shown in FIG. 10 for explaining the unnecessary circumferential displacement, in the position phase of the rotating standing wave having an antinode at the midpoint between FIGS. 8A and 8B, the direction of the circumferential displacement As a result, the horizontal balance in either direction remains as a result of cancellation. Since the horizontal rotation component is unnecessary in the tilt rotation, it is necessary to cancel the feed movement component in the horizontal rotation direction.

  11A and 11B are explanatory diagrams of the behavior of the contact portion due to the stationary standing wave, and the behavior of the contact portions 3a to 3c due to the out-of-plane vibration that is the stationary standing wave is shown in the horizontal direction (ring (Normal direction of side surface) Since the actual amplitude is in the micron order, the amplitude is enlarged and visualized. If the spatial position phase between the antinode of the stationary standing wave and the contact portion completely coincides, the circumferential displacement does not occur as shown in FIG. However, since there is no perfect coincidence due to mechanical causes such as processing accuracy and assembly accuracy, the distal ends of the contact portions 3a to 3c are displaced in the circumferential direction as shown in FIG. Based on this, the second embodiment will be described in detail below.

<Configuration and Operation of Control Device According to Second Embodiment>
FIG. 12 is a block diagram showing the configuration of the control device of the vibration wave drive device according to the second embodiment of the present invention. Elements common to those in FIG. To do.

  The control device in the present embodiment has a configuration in which an additional standing wave generator 140 is added to the configuration shown in FIG. When the rotation axis and the rotation speed are given as the target values of the tilt rotation, the standing wave of the out-of-plane tertiary vibration at the position where the spatial position phase is shifted by 90 degrees (additional standing wave: third) Amplitude / phase difference (vs. standing wave) is determined. This command value is sent to the additional standing wave generator 140. The signal generator 142 generates a drive signal for generating an additional standing wave and supplies it to the vibration wave motor 130 to drive the tilt rotation.

  An electrode group for generating the additional standing wave is indicated by A in FIG. The A electrode group and the F electrode group are alternately arranged at positions shifted by 90 degrees, and the surface is obtained by exciting the additional standing wave with a phase difference of 90 degrees with respect to the fixed standing wave. A traveling wave of the outer tertiary vibration can be generated. The amplitude of the additional standing wave does not affect the amount of displacement in the out-of-plane direction of the contact portion due to the fixed standing wave, so it is not related to the feed movement in the tilt direction due to the combination of the stationary standing wave and the rotating standing wave. Can be thought of as a thing. Therefore, the amplitude of the additional standing wave, that is, the feed movement by the traveling wave can be controlled independently.

  Depending on the amplitude value of the additional standing wave, the amplitude distribution of the traveling wave by the two standing waves is as shown in FIG. FIG. 13 is a graph showing the amplitude distribution of traveling waves by two standing waves. In the figure, the vertical axis represents the traveling wave amplitude, and the horizontal axis represents the spatial position phase of the ring-type vibrator 4, and contact portions are arranged at positions X1, X2, and X3 in the figure. At this time, the X1, X2, and X3 positions (60 degrees, 180 degrees, and 300 degrees) of the three contact portions coincide with the positions of the antinodes of the fixed standing wave, and the traveling wave amplitude at this position is fixed standing. Determined by the wave amplitude command value.

  In addition, since the positions of 0 degrees, 120 degrees, and 240 degrees, which are intermediate points between adjacent contact portions, are also antinode positions of the stationary standing wave, the traveling wave amplitude is the same as that of the contact portion. If the contact portion position and the peak of the stationary standing wave are ideally matched, the circumferential displacement of the tip of the contact portion due to only the stationary standing wave is zero. And since the position phase of A electrode group and F electrode group has shifted | deviated 90 degree | times, the amplitude in the middle point of the antinode of an adjacent fixed standing wave is an amplitude command value of an additional standing wave. That is, FIG. 13 shows the traveling wave amplitude distribution when “0.2”, “0.8”, and “1.5” are set for the amplitude 1 of the fixed standing wave.

  The control device according to the present embodiment generates a traveling wave in a direction in which this component is canceled when an unnecessary feed motion in the horizontal rotation direction occurs as in the above two examples. The traveling direction of the traveling wave is determined by the phase difference between the additional standing wave and the fixed standing wave, and the circumferential amplitude at the tip of the contact portion due to the traveling wave is determined by the amplitude of the additional standing wave.

  From the above, it is possible to freely control the circumferential feed movement by controlling the phase difference between the fixed standing wave and the additional standing wave that form the traveling wave and the amplitude of the additional standing wave. It is possible to cancel the feed movement component in the horizontal rotation direction.

  In the first and second embodiments, as shown in FIG. 5, the contact portions are arranged at intervals of one wavelength of the fixed constant material wave at the position of the F + electrode group that excites the fixed constant material wave. -Even if it is arranged at the position of the electrode group, it is the same. Further, the present driving principle is established even when the F electrode group is arranged at all the positions in half wavelength steps. Further, when there are six F + electrodes, that is, when the fixed fixed material wave is out-of-plane sixth-order vibration, it is possible to provide three contact portions at intervals of two wavelengths. Note that the three contact portions do not necessarily need to be equally spaced, and the contact portions may be arranged after confirming that the position of the rotating shaft is variable based on the balance of the driving force.

[Third Embodiment]
<Configuration of Control Device of Third Embodiment>
FIG. 14 is a block diagram showing the configuration of the control device for the vibration wave driving device according to the third embodiment of the present invention.

  A tilt rotation component and a horizontal rotation component are calculated from the rotation axis and rotation speed as a target value of given arbitrary axis rotation. The amplitude / phase difference between the stationary standing wave (out-of-plane vibration) and the rotating standing wave (in-plane vibration) and the rotating standing wave (in-plane) are obtained from the characteristics of the vibration wave motor 130 obtained in advance. The spatial position phase of (vibration) is determined. Further, the amplitude and phase difference (vs. stationary wave) of the additional standing wave (out-of-plane vibration) is also determined. These command values are sent to the standing wave generators 110, 120, and 140, and the signal generators 113, 114, 121, and 142 generate driving signals for generating the standing waves and generate vibrations. It is input to the wave motor 130 and the tilt rotation is driven.

  In the present embodiment, the configuration of each of the standing wave generators 110, 120, and 140 shown in FIG. 12 shown in the second embodiment is used as it is, and the control for canceling the unnecessary feed motion component in the horizontal rotation direction is used. The function is left. Further, the configuration is such that the amplitude and phase difference of the additional standing wave are set so as to positively generate horizontal rotation. Therefore, it is possible to realize driving around an arbitrary axis by arbitrarily determining the ratio of the feed motion component in the horizontal rotation direction and the feed motion component in the tilt rotation direction.

  That is, in the configuration of the present embodiment, a sensor unit 150 is provided in which detection means for measuring the rotation axis and the number of rotations of the rotating body is arranged. A tilt rotation component 151 and a horizontal rotation component 152 are calculated from the detection data of the sensor unit 150, and each standing wave command value is controlled by feedback of each component data.

  FIG. 15 is a block diagram showing a configuration of a control device for a vibration wave drive device according to a modification of the third embodiment of the present invention.

  As shown in FIG. 15, the configuration of this control device is provided with detection means for measuring or calculating the absolute position of the rotating body in the sensor unit 153. The ideal trajectory from the current position to the target position obtained by the sensor unit 153 is recalculated by the corrected rotation axis calculation unit 154, and a new corrected rotation axis command value is returned to the upper left arbitrary axis setting for control. is there. Of course, these sensor units 153 can be used in combination, and can also be installed in the control devices of the first and second embodiments.

  In the system according to the third embodiment, for example, when the contact state (mainly the friction coefficient) changes due to long-time driving or driving environment, or when the characteristics of the vibration wave motor are not obtained in advance. Suppose. Therefore, it is desirable that the control parameters are automatically adjusted based on the relationship between the data from the sensor units 150 and 153 and the input signals, and the parameters are updated sequentially. This is because, in a vibration wave motor capable of rotating around an arbitrary axis, a difference in progress of deterioration of each contact portion is caused by a frequently used rotating shaft, and a change from an initial control parameter tends to be large. In addition, even if there are two of the same initial motor characteristics, the characteristics are likely to vary greatly depending on the subsequent use conditions.

  In addition, the objective of this invention is achieved by performing the following processes. That is, a storage medium that records a program code of software that realizes the functions of the above-described embodiments is supplied to a system or apparatus, and a computer (or CPU, MPU, etc.) of the system or apparatus is stored in the storage medium. This is the process of reading the code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Moreover, the following can be used as a storage medium for supplying the program code. For example, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, ROM or the like. Alternatively, the program code may be downloaded via a network.

  Further, the present invention includes a case where the function of the above-described embodiment is realized by executing the program code read by the computer. In addition, an OS (operating system) running on the computer performs part or all of the actual processing based on an instruction of the program code, and the functions of the above-described embodiments are realized by the processing. Is also included.

  Furthermore, a case where the functions of the above-described embodiment are realized by the following processing is also included in the present invention. That is, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

2 Piezoelectric elements 3a to 3c Contact section 4 Vibrator 13 Rotating body 110 Rotating standing wave generating section 120 Fixed standing wave generating section 130 Vibration wave motor 140 Additional standing wave generating section

Claims (11)

Comprising a vibrator having a plurality of contact parts with a rotating body,
The vibrator is
A first electrode group supplied with a first drive signal for generating a first standing wave in the vibrator;
A second electrode group that is supplied with a second drive signal and a third drive signal, respectively, for generating at least two standing waves that are combined to generate a second standing wave in the vibrator; and A third electrode group;
Have
In the second standing wave, the spatial position phase of the antinode is set by the second drive signal and the third drive signal,
The first standing wave is an in-plane vibration standing wave and the second standing wave is an out-of-plane vibration standing wave, or the first standing wave is an out-of-plane vibration standing wave and the second The standing wave is an in-plane vibration standing wave,
The plurality of contact portions are vibration wave driving devices arranged at intervals of an integral multiple of 1/2 of the wavelength of the first standing wave.   The spatial position phase of the antinode of the second standing wave changes during rotation in an inclined direction having a rotation axis in a plane including the rotation center of the rotating body and having the center axis of the vibrator as a normal vector The vibration wave driving device according to claim 1, wherein the position of the rotation axis of the rotation in the tilt direction is controlled by doing so.   The vibration wave drive according to claim 2, wherein a spatial position phase of an antinode of the second standing wave is controlled by an amplitude ratio of the at least two standing waves constituting the second standing wave. apparatus. The transducer is combined with the first standing wave to generate a traveling wave in the transducer, and a fourth drive signal is applied to generate a third standing wave. Having an electrode group,
4. The vibration wave driving device according to claim 2, wherein the traveling wave excites a horizontal rotational feed motion with a center axis of the vibrator as a rotation axis. 5.   5. The vibration wave driving device according to claim 4, wherein the traveling wave is generated in a direction that cancels an unnecessary horizontal feed motion in a sum of feed motions excited by the plurality of contact portions.   The horizontal rotational feed movement is controlled by the phase difference between the first standing wave and the third standing wave forming the traveling wave and the amplitude of the third standing wave. The vibration wave driving device according to claim 4, wherein the vibration wave driving device is provided.   7. The rotation axis of rotation of the rotating body is defined by a ratio of the feed movement component of the rotation in the horizontal direction and the feed movement component of the rotation in the tilt direction. Vibration wave drive device.   The temporal phase difference between the first standing wave and the third standing wave forming the traveling wave is 90 degrees, according to any one of claims 4 to 7, The vibration wave driving device described.   The first standing wave is an even-order driving vibration, and the second standing wave is an odd-order driving vibration, or the first standing wave is an odd-order driving vibration. The vibration wave driving device according to claim 1, wherein the second standing wave is an even-order driving vibration.   10. The vibration wave driving device according to claim 1, wherein the plurality of contact portions include a contact portion having a phase position that matches the spatial position phase of the antinode of the first standing wave. .   10. The vibration wave driving device according to claim 4, wherein the plurality of contact portions include a contact portion having a phase position that does not coincide with a spatial position phase of the antinode of the first standing wave.

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