JP2017017969A - Piezoelectric driving device, robot, and driving method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly move a position of a driven member.SOLUTION: A piezoelectric driving device comprises: a piezoelectric driving section driving a driven member; and a driving circuit driving the piezoelectric driving section. The driving circuit activates the piezoelectric driving section by speed control. Thus, a repeat of operation and stoppage of the piezoelectric driving section is suppressed, and a position of the driven member is smoothly moved.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a piezoelectric driving device, a robot, and a driving method thereof.

  Piezoelectric actuators (piezoelectric driving devices) that drive a driven body (driven member) by vibrating a vibrating body with piezoelectric elements are used for various operation controls of various devices. For example, in Patent Document 1, a plurality of deceleration sections to a set deceleration start position and a target position are controlled while increasing / decreasing a drive frequency based on a speed curve set when a vibration wave motor (piezoelectric actuator) is decelerated. It is disclosed that the pulse width is gradually decreased from the initial width to reach the minimum pulse width for each area toward the target position, the minimum pulse width is reached, the state is maintained, and the target position is stopped. Yes.

JP 2007-209179 A

  Conventionally, when the piezoelectric actuator is operated so that the position of movement of the driven body follows a locus of a predetermined position (rotation position (angle), linear position (displacement), etc.), the target position in the locus for each period Are sequentially specified, the piezoelectric actuator is operated, and when the target position is reached, the control for stopping the operation of the piezoelectric actuator is repeated (position control). In this case, the operation speed of the piezoelectric actuator is a predetermined speed (usually the maximum operation speed).

  However, in the case of the above position control, for example, when the movement to each target position is completed, the operation of the piezoelectric actuator is stopped. Therefore, the operation and the stop are repeated in each cycle, and smooth operation control is performed. There was a problem that was not done. There is also a problem that a stop sound is generated due to a sudden stop operation. None of the above-mentioned patent documents 1 and 2 has any description or suggestion regarding the above-mentioned problem.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

(1) According to one aspect of the present invention, a piezoelectric driving device is provided. The piezoelectric drive device includes a piezoelectric drive unit that drives a driven member, and a drive circuit that drives the piezoelectric drive unit. The drive circuit operates the piezoelectric drive unit by speed control.
According to this aspect, since the piezoelectric drive unit is operated not by position control but by speed control, it is possible to suppress the operation and stop of the piezoelectric drive unit from being repeated as compared with the case of performing position control. The position can be moved smoothly.

(2) In the piezoelectric drive device according to the above aspect, the drive circuit moves the position of the driven member from the first position according to a movement trajectory based on a target position of the driven member that is instructed at regular intervals. When moving to the second position, when the target position at the second cycle timing one cycle after the first cycle timing is instructed at the first cycle timing, the target position and the first position A moving speed to the target position is determined based on a current position of the driven member at a cycle timing, and the piezoelectric is moved at the determined moving speed from the first cycle timing to the second cycle timing. Speed control for operating the drive unit may be executed.
According to this aspect, when the target position is instructed at the first cycle timing, the piezoelectric drive unit is operated at the determined moving speed from the first cycle timing to the second cycle timing. When the movement to the target position is completed, the operation of the piezoelectric drive unit is stopped and the operation and stop of the piezoelectric drive unit are suppressed in each cycle, and the position of the driven member can be moved smoothly. . Further, since the moving speed is determined based on the target position and the current position, the piezoelectric drive unit can be operated so that the locus of the current position approaches the locus of the target position.

(3) In the piezoelectric drive device of the above aspect, the drive unit is to be obtained based on the previous cycle target position and the target position that are instructed at the previous cycle timing one cycle before the first cycle timing. The movement speed to the target position may be determined by correcting the movement speed based on the previous cycle target position and the current position.
According to this aspect, by correcting the moving speed, the piezoelectric drive unit can be operated so that the locus of the current position approaches the locus of the target position.

(4) In the piezoelectric driving device according to the aspect described above, when the target position is the second position, the driving circuit performs the piezoelectric driving when the position of the driven member becomes the second position. Position control for stopping the unit may be executed.
According to this aspect, the operation of the piezoelectric driving unit can be stopped with high accuracy at the second position.

  The present invention can be realized in various forms. For example, in addition to the piezoelectric driving device, the driving method of the piezoelectric driving device, the robot equipped with the piezoelectric driving device, the driving method of the robot equipped with the piezoelectric driving device, It can be realized in various forms such as an electronic component conveying device, a liquid feeding pump, and a medication pump.

It is a block diagram which shows schematic structure of the piezoelectric drive device as 1st Embodiment. It is a schematic block diagram of a piezoelectric drive part. It is a top view of a diaphragm. It is explanatory drawing which shows the electrical connection state of a piezoelectric drive part and a drive circuit. It is explanatory drawing which shows the example of operation | movement of a piezoelectric drive part. It is explanatory drawing which shows the structure of a speed control part and a position control part. It is explanatory drawing which shows the example of the movement operation | movement of the position of a to-be-driven member by the speed control of a speed control part, and the position control of a position control part. It is explanatory drawing which shows the structure of the speed control part and position control part in 2nd Embodiment. It is sectional drawing of the piezoelectric drive part as other embodiment of this invention. It is a plane schematic diagram of the piezoelectric drive part as other embodiment of this invention. It is explanatory drawing which shows an example of the robot using a piezoelectric drive device. It is explanatory drawing of the wrist part of a robot. It is explanatory drawing which shows an example of the liquid feeding pump using a piezoelectric drive device.

A. First embodiment:
A1. Piezoelectric drive configuration:
FIG. 1 is a block diagram showing a schematic configuration of a piezoelectric driving apparatus 1000 as the first embodiment. The piezoelectric driving device 1000 includes a piezoelectric driving unit 10 that drives a driven member (also referred to as “driven body”) 50, a driving circuit 30 that drives the piezoelectric driving unit 10, and an encoder that detects the position of the driven member 50. (Position detection unit) 40. In this example, the driven member 50 is a rotor. In this case, the position of the driven member 50 is a rotational position, that is, an angle, and the encoder 40 can use an encoder that detects the rotational angle, for example, an encoder that detects the rotational angle, such as a rotary encoder. . However, the driven member 50 is not limited to the rotor, and may be a driven member that linearly operates. In this case, an encoder that detects the position of the linear displacement is used as the encoder 40.

  2A is a schematic plan view of the piezoelectric drive unit 10, and FIG. 2B is a cross-sectional view taken along the line BB. The piezoelectric drive unit 10 includes a vibration plate 200 and two piezoelectric vibration members 100 disposed on both surfaces (first surface 211 and second surface 212) of the vibration plate 200, respectively. The piezoelectric vibrating body 100 includes a substrate 120, a first electrode 130 formed on the substrate 120, a piezoelectric body 140 formed on the first electrode 130, and a second electrode formed on the piezoelectric body 140. An electrode 150. The first electrode 130 and the second electrode 150 sandwich the piezoelectric body 140. The two piezoelectric vibrators 100 are arranged symmetrically about the diaphragm 200. Since the two piezoelectric vibrators 100 have the same configuration, the configuration of the piezoelectric vibrator 100 on the upper side of the diaphragm 200 will be described below unless otherwise specified.

The substrate 120 of the piezoelectric vibrating body 100 is used as a substrate for forming the first electrode 130, the piezoelectric body 140, and the second electrode 150 by a film forming process. The substrate 120 also has a function as a diaphragm that performs mechanical vibration. The substrate 120 can be formed of, for example, Si, Al ₂ O ₃ , ZrO ₂ or the like. As the Si substrate 120, for example, a Si wafer for semiconductor manufacturing can be used. In this embodiment, the planar shape of the substrate 120 is a rectangle. The thickness of the substrate 120 is preferably in the range of 10 μm to 100 μm, for example. If the thickness of the substrate 120 is 10 μm or more, the substrate 120 can be handled relatively easily during the film forming process on the substrate 120. If the thickness of the substrate 120 is 100 μm or less, the substrate 120 can be easily vibrated according to the expansion and contraction of the piezoelectric body 140 formed of a thin film.

  The first electrode 130 is formed as one continuous conductor layer formed on the substrate 120. On the other hand, as shown in FIG. 2A, the second electrode 150 is divided into five conductor layers 150a to 150e (also referred to as “second electrodes 150a to 150e”). The second electrode 150e at the center is formed in a rectangular shape covering almost the entire length of the substrate 120 at the center in the width direction of the substrate 120. The other four second electrodes 150 a, 150 b, 150 c, and 150 d have the same planar shape and are formed at the four corner positions of the substrate 120. In the example of FIG. 2, both the first electrode 130 and the second electrode 150 have a rectangular planar shape. The first electrode 130 and the second electrode 150 are thin films formed by sputtering, for example. As a material of the first electrode 130 and the second electrode 150, for example, any material having high conductivity such as Al (aluminum), Ni (nickel), Au (gold), Pt (platinum), Ir (iridium) or the like is used. Is available. Instead of the first electrode 130 being one continuous conductor layer, the first electrode 130 may be divided into five conductor layers having substantially the same planar shape as the second electrodes 150a to 150e. In addition, wiring (or wiring layer and insulating layer) for electrical connection between the second electrodes 150a to 150e, and electrical connection between the first electrode 130 and the second electrodes 150a to 150e and the drive circuit The wiring for the purpose (or the wiring layer and the insulating layer) is not shown in FIG.

  The piezoelectric body 140 is formed as five piezoelectric layers having substantially the same planar shape as the second electrodes 150a to 150e. Alternatively, the piezoelectric body 140 may be formed as one continuous piezoelectric layer having substantially the same planar shape as the first electrode 130. Five piezoelectric elements 110a to 110e (FIG. 2A) are configured by a laminated structure of the first electrode 130, the piezoelectric body 140, and the second electrodes 150a to 150e.

  Of the five piezoelectric elements 110a to 110e, four piezoelectric elements 110a to 110d are a pair of piezoelectric elements 110a and 110d at a first diagonal, and a pair of piezoelectric elements 110b and 110c at a second diagonal. These are symmetric with respect to the center line CX along the longitudinal direction of the piezoelectric vibrating body 100. The remaining piezoelectric element 110e is sandwiched between the pair of piezoelectric elements 110a and 110d and the other pair of piezoelectric elements 110b and 110c, and is at the center position in the width direction of the piezoelectric vibrating body 100 along the center line CX. Hereinafter, the pair of piezoelectric elements 110a and 110d is also referred to as “first piezoelectric elements 110a and 110d”, and the other pair of piezoelectric elements 110b and 110c is also referred to as “second piezoelectric elements 110b and 110c”. The central piezoelectric element 110e is also referred to as “third piezoelectric element 110e”.

The piezoelectric body 140 is a thin film formed by, for example, a sol-gel method or a sputtering method. As a material of the piezoelectric body 140, any material exhibiting a piezoelectric effect such as ceramics having an ABO ₃ type perovskite structure can be used. Examples of ceramics having an ABO ₃ type perovskite structure include lead zirconate titanate (PZT), barium titanate, lead titanate, potassium niobate, lithium niobate, lithium tantalate, sodium tungstate, zinc oxide, titanium Barium strontium acid (BST), strontium bismuth tantalate (SBT), lead metaniobate, lead zinc niobate, lead scandium niobate, or the like can be used. It is also possible to use a material exhibiting a piezoelectric effect other than ceramic, such as polyvinylidene fluoride and quartz. The thickness of the piezoelectric body 140 is preferably in the range of, for example, 50 nm (0.05 μm) to 20 μm. A thin film of the piezoelectric body 140 having a thickness in this range can be easily formed using a film forming process. If the thickness of the piezoelectric body 140 is 0.05 μm or more, a sufficiently large force can be generated according to the expansion and contraction of the piezoelectric body 140. Moreover, if the thickness of the piezoelectric body 140 is 20 μm or less, the piezoelectric vibrating body 100 (piezoelectric drive unit 10) can be sufficiently downsized.

  FIG. 3 is a plan view of the diaphragm 200. The diaphragm 200 has a rectangular-shaped vibrating body portion 210 and three connecting portions 220 that extend from the left and right long sides of the vibrating body portion 210, respectively. Two attachment portions 230 are connected to each other. In FIG. 2, the vibrating body portion 210 is hatched for convenience of illustration. The attaching part 230 is used for attaching the piezoelectric driving part 10 to another member with a screw 240. The diaphragm 200 is formed of a material such as silicon, silicon compound, stainless steel, aluminum, aluminum alloy, titanium, titanium alloy, copper, copper alloy, iron-nickel alloy or the like, metal oxide, or diamond. It is possible.

  The piezoelectric vibrating body 100 (FIG. 2) is bonded to the upper surface (first surface) and the lower surface (second surface) of the vibrating body portion 210 using an adhesive. The ratio of the length L to the width W of the vibrating body part 210 is preferably L: W = about 7: 2. This ratio is a preferable value for performing ultrasonic vibration (described later) in which the vibrating body portion 210 bends left and right along the plane. The length L of the vibrating body portion 210 can be set in a range of 0.1 mm to 30 mm, for example, and the width W can be set in a range of 0.05 mm to 8 mm, for example. In addition, in order for the vibrating body part 210 to perform ultrasonic vibration, the length L is preferably set to 50 mm or less. The thickness of the vibrating body part 210 (thickness of the vibration plate 200) can be in the range of 20 μm to 700 μm, for example. If the thickness of the vibrating body portion 210 is 20 μm or more, the vibrating body portion 210 has sufficient rigidity to support the piezoelectric vibrating body 100. Further, if the thickness of the vibrating body portion 210 is 700 μm or less, a sufficiently large deformation can be generated according to the deformation of the piezoelectric vibrating body 100.

A contact member 20 (also referred to as a “projection portion” or an “action portion”) is provided on one short side of the diaphragm 200. The contact member 20 is a member that is in contact with the driven body and applies force to the driven body. The contact member 20 is preferably formed of a durable material such as ceramics (for example, Si, SiC, Al ₂ O ₃ , Zr0 ₂ ).

  FIG. 4 is an explanatory diagram showing an electrical connection state between the piezoelectric drive unit 10 and the drive circuit 30. The drive circuit 30 includes a drive control unit 32, a speed control unit 34, a position control unit 36, and a drive voltage generation unit 38. The speed control unit 34, the position control unit 36, and the drive voltage generation unit 38 execute control operations in accordance with the control signals Cdv, Cv, and Cp respectively supplied from the drive control unit 32.

  The drive control unit 32 forms a movement locus of the target position from the start position (first position) to the final position (second position) as the movement locus of the position (rotational position) of the driven member (rotor) 50. A plurality of target positions to be received can be received and held in advance or sequentially from a control unit (not shown) of a device (for example, a robot) that uses the piezoelectric driving device 1000. When the drive control unit 32 moves the position of the driven member 50 in accordance with the movement locus of the target position, the drive voltage is based on the speed control of the speed control unit 34 and the position control of the position control unit 36, as will be described later. The operation of the piezoelectric drive unit 10 driven by the generation unit 38 is controlled so that the movement of the position of the driven member 50 follows the movement locus of the target position.

  The speed control unit 34 synchronizes with each cycle timing of the timing signal Sts having a predetermined cycle Ts, and the target position Pt of the driven member 50 supplied (instructed) from the drive control unit 32 and the target position Pt supplied from the encoder 40. Based on the position Pr (also referred to as “current position”) Pr of the drive member 50, the movement speed Vt to the instructed target position Pt is determined, and the obtained movement speed Vt is supplied to the drive voltage generator 38. The drive voltage generation unit 38 drives the piezoelectric drive unit 10 according to the received moving speed Vt. Thereby, the speed control unit 34 performs speed control according to the moving speed Vt obtained based on the target position Pt and the current position Pr of the driven member 50, thereby operating the piezoelectric driving unit 10, The movement of the position of the driven member 50 is controlled. The configuration and operation of the speed control unit 34 will be further described later.

  The position control unit 36 performs position control when the target position Pt of the driven member 50 supplied (instructed) from the drive control unit 32 is the final position (second position) of the movement locus. The position control in the position control unit 36 will be schematically described. The current position Pr of the driven member 50 detected by the encoder 40 is monitored, and when the current position Pr reaches the final position, the drive voltage generation unit 38 is informed. The stop signal stp is supplied to stop the drive operation of the piezoelectric drive unit 10 by the drive voltage generation unit 38, thereby making the position of the driven member 50 the final position. The configuration and operation of the position controller 36 will be further described later.

  The drive voltage generator 38 generates a drive voltage including an AC component. As the drive voltage including an AC component, an AC drive voltage consisting only of an AC component that fluctuates on the positive side and the negative side with respect to the ground potential, a drive voltage with offset including an AC component and a DC offset (DC component) It is preferable that at least one of them can be generated. The AC component of the drive voltage is preferably an electrical signal having a frequency close to the mechanical resonance frequency of the piezoelectric drive unit 10, ideally a resonance frequency. The AC component waveform is typically a sine wave, but may have a waveform other than a sine wave. The direct current component does not need to be strictly constant and may vary somewhat. For example, the DC component may vary within ± 10% of the average value. The drive voltage generation unit 38 and the electrodes 130 and 150 of the piezoelectric drive unit 10 are connected as follows.

  Among the five second electrodes 150 a to 150 e of the piezoelectric driving unit 10, the second electrodes 150 a and 150 d of the pair of first piezoelectric elements 110 a and 110 d at the first diagonal are electrically connected to each other via the wiring 151. The second electrodes 150b and 150c of the pair of second piezoelectric elements 110b and 110c of the other second diagonal are also electrically connected to each other via the wiring 152. These wirings 151 and 152 may be formed by a film forming process, or may be realized by wire-like wiring. The three second electrodes 150b, 150e, 150d on the right side of FIG. 4 and the first electrode 130 (FIG. 2) are electrically connected to the drive circuit 30 via wirings 310, 312, 314, 320. . In the example of FIG. 3, the wiring 320 is grounded. The first piezoelectric elements 110a and 110d, the second piezoelectric elements 110b and 110c, and the third piezoelectric element 110e are connected between the ground wiring 320 and the other wirings 310, 312, and 314. 38 is connected in parallel.

  The drive voltage generation unit 38 applies the drive voltage including an AC component between the second electrodes 150a and 150d of the pair of first piezoelectric elements 110a and 110d and the first electrode 130, thereby causing the piezoelectric drive unit 10 to move. It is possible to rotate the driven member (rotor) 50 in contact with the contact member 20 in a predetermined rotation direction by ultrasonic vibration. The driven member 50 that contacts the contact member 20 by applying a drive voltage including an AC component between the second electrode 150b, 150c of the pair of second piezoelectric elements 110b, 110c and the first electrode 130. Can be rotated in the opposite direction. Such voltage application is performed simultaneously on the two piezoelectric vibrating bodies 100 provided on both surfaces of the diaphragm 200. Note that the wirings (or wiring layers and insulating layers) constituting the wirings 151, 152, 310, 312, 314, and 320 shown in FIG. 4 are not shown in FIG.

  FIG. 5 is an explanatory diagram illustrating an example of the operation of the piezoelectric driving unit 10. The contact member 20 of the piezoelectric drive unit 10 is in contact with the outer periphery of the driven member 50 formed of a rotor. In the example illustrated in FIG. 5, the drive voltage generation unit 38 (FIG. 4) of the drive circuit 30 has a drive voltage between the second electrodes 150 a and 150 d and the first electrode 130 of the pair of first piezoelectric elements 110 a and 110 d. Is applied, and the pair of first piezoelectric elements 110a and 110d expands and contracts in the direction of the arrow x in FIG. In response to this, the vibrating member 210 of the piezoelectric driving unit 10 is bent in the plane of the vibrating member 210 and deformed into a meandering shape (S shape), and the tip of the contact member 20 reciprocates in the direction of the arrow y. Or elliptical motion. As a result, the driven member 50 rotates around the center 51 in a predetermined direction z (clockwise direction in FIG. 5). That is, the pair of first piezoelectric elements 110a and 110d bend the diaphragm 200 in cooperation. The three connection portions 220 of the diaphragm 200 described with reference to FIG. 3 are provided at the positions of the vibration nodes of the vibrating body portion 210. The drive voltage generator 38 of the drive circuit 30 applies a drive voltage between the second electrodes 150b and 150c (FIG. 4) of the other pair of second piezoelectric elements 110b and 110c and the first electrode 130. In some cases, the driven member 50 rotates in the opposite direction. In this case, the pair of second piezoelectric elements 110b and 110c bend the diaphragm 200 in cooperation. In addition, if the same voltage as a pair of 2nd electrode 150a, 150d (or another pair of 2nd electrode 150b, 150c) is applied to the 2nd electrode 150e of the center 3rd piezoelectric element 110e, the piezoelectric drive part 10 will be described. Therefore, the force applied from the contact member 20 to the driven member 50 can be increased. Such an operation of the piezoelectric drive unit 10 (or the piezoelectric vibrator 100) is described in Prior Art Document 1 (Japanese Patent Laid-Open No. 2004-320979 or corresponding US Pat. No. 7,224,102). The disclosure of which is incorporated by reference.

A2. Configuration and operation of speed controller and position controller:
FIG. 6 is an explanatory diagram showing configurations of the speed control unit 34 and the position control unit 36. The speed control unit 34 includes a delay unit 342, a sample hold unit (hereinafter abbreviated as “S / H unit”) 344, and a moving speed calculation unit 346. In the speed control unit 34, the drive control unit 32 (FIG. 4) starts to control the movement of the position (rotation position) of the driven member 50 according to the movement locus of the target position, and the control signal Cv is received from the drive control unit 32. When supplied, the operation of each block is started. Note that the movement locus of the target position is composed of a plurality of target positions from the start position (first position) to the final position (second position) as described above, and is held by the drive control unit 32. Shall.

  The delay unit 342 is a delay circuit that delays the target position Pt of the driven member 50 supplied (instructed) from the drive control unit 32 at each cycle timing of the timing signal Sts of the cycle Ts for one cycle (cycle Ts). is there. The S / H unit 344 is a block that samples (stores) an input signal (data) at each cycle timing and holds (holds) it until the next cycle timing. For example, at the cycle timing (also referred to as “first cycle timing”) of the nth cycle (where n is an integer greater than or equal to 0) (also referred to as “first cycle timing”), the nth target position Pt (n) (“first Suppose that a target position in a second cycle timing one cycle after the cycle timing is supplied (instructed). In this case, the S / H unit 344 is supplied (instructed) together with the data of the nth target position Pt (n) from the drive control unit 32 at the previous cycle timing one cycle before the first cycle timing. Data of the (n−1) th target position (hereinafter also referred to as “pre-cycle target position”) Pt (n−1) is input, and data of the current position Pr supplied from the encoder 40 is input. In the S / H unit 344, at the first cycle timing, the target position Pt (n), the previous cycle target position Pt (n−1), and the previous cycle target position Pt (n−) at the second cycle timing. The current position Pr (n-1) corresponding to 1) is sampled and held.

The movement speed calculation unit 346 of the speed control unit 34 calculates a movement speed Vt (n) for moving the current position Pr of the driven member 50 to the target position Pt (n) during the period Ts, using the following equation (1). The moving speed Vt (n) calculated based on (3) and determined by the calculation is supplied to the drive voltage generator 38.
Vt (n) = Vtr (n) + Vtc (n) (1)
Vtr (n) = [Pt (n) −Pt (n−1)] / Ts (2)
Vtc (n) = k · [Pt (n−1) −Pr (n−1)] / Ts (3)
Here, Vtr (n) is a planned movement speed for moving the driven member 50 from the previous cycle target position Pt (n−1) to the target position Pt (n). Vtc (n) is a speed correction amount according to the difference between the previous cycle target position Pt (n-1) and the current position Pr (n-1). k is a correction coefficient, and Ts is the length of one cycle. The correction coefficient k is such that the movement trajectory of the position Pr of the driven member 50 suppresses the difference between the previous cycle target position Pt (n−1) and the current position Pr (n−1) corresponding thereto, and the target position For example, the adjustment is performed in advance in an actual apparatus within a range of 0.8 to 1.2 so as to approach the movement locus of Pt.

In addition, when the moving speed Vt (n) to the target position Pt (n) obtained by the above formula is excessively large, and the moving speed Vt (n) and the movement to the previous cycle target position Pt (n−1). If the difference from the speed Vt (n−1) is excessively large, the change in the position Pr of the driven member 50 becomes abrupt, which may not be preferable in terms of smooth operation. Therefore, it is preferable to limit the moving speed Vt (n) to a range that satisfies the following expressions (4) and (5).
| Vt (n) | <Vmax (4)
| Vt (n) −Vt (n−1) | <ΔVmax (5)
Here, Vmax is the maximum settable moving speed (upper limit allowable speed), and ΔVmax is the maximum settable moving speed difference (upper limit allowable speed difference). Vmax and ΔVmax are adjusted to values acceptable as a smooth operation.

  When the moving speed Vt (n) does not satisfy the above expression (4), the moving speed Vt (n) is set to satisfy | Vt (n) | = Vmax. When the moving speed Vt (n) does not satisfy the above equation (5), the moving speed Vt (n) is set so that | Vt (n) −Vt (n−1) | = ΔVmax. . As a result, it is possible to perform smooth operation control while suppressing rapid fluctuations. However, these restrictions do not have to be executed.

  The drive voltage generation unit 38 (FIG. 4) that has received the movement speed Vt (n) from the speed control unit 34 has a relational expression, table data (not shown), etc. that indicate the relationship between the movement speed and the drive voltage prepared in advance. Based on the above, a drive voltage corresponding to the moving speed Vt (n) is generated and applied between the second electrode 150 and the first electrode 130 of the piezoelectric element 110 of the piezoelectric drive unit 10. Thus, as described above, the drive circuit 30 can drive the driven member 50 by ultrasonically vibrating the piezoelectric drive unit 10 and move the position Pr of the driven member 50.

  As described above, the speed control unit 34 moves based on the target position Pt supplied (instructed) from the drive control unit 32 and the position (current position) Pr of the driven member 50 supplied from the encoder 40. The speed Vt is obtained. The drive voltage generation unit 38 generates a drive voltage corresponding to the moving speed Vt obtained by the speed control unit 34 and operates the piezoelectric drive unit 10. Therefore, the speed control unit 34 operates the piezoelectric drive unit 10 by speed control.

  On the other hand, the position control unit 36 includes an S / H unit 364 and a position comparison unit 366. When the final position (second position) is supplied (instructed) as the target position Pt from the drive control unit 32, the position control unit 36 starts the operation of each block when the control signal Cp is supplied.

  The S / H unit 364 is a block similar to the S / H unit 344 of the speed control unit 34, and samples and holds the final position Pe supplied (instructed) as the target position Pt from the drive control unit 32. For example, when the final position Pe is supplied as the target position Pt (n) from the drive control unit 32, the final position Pe is sampled and held in the S / H unit 364 as the target position Pt (n). In parallel with the operation of the position controller 36, the speed controller 34 also operates as described above to determine the moving speed Vt (n) to the final position Pe, and the determined moving speed Vt (n). The piezoelectric drive unit 10 is operated.

  The position comparison unit 366 receives from the encoder 40 (FIG. 4) the current position Pr of the driven member 50 that moves as the piezoelectric driving unit 10 operates at the moving speed Vt. The detection cycle of the current position Pr at this time is preferably sufficiently shorter than the speed control cycle Ts (for example, 1/60 to 1/20). The position comparison unit 366 compares the received current position Pr with the final position Pe. If the current position Pr matches the final position Pe, the position comparison unit 366 generates a stop signal stp as a drive voltage generation unit 38, a movement speed calculation unit 346, and a drive. Output to the control unit 32, the operation of the piezoelectric drive unit 10 is immediately stopped, and the movement of the current position Pr of the driven member 50 is stopped at the final position Pe.

  As described above, the position control unit 36, when the target position Pt supplied (instructed) from the drive control unit 32 is the final position Pe, the position (current position) of the driven member 50 supplied from the encoder 40. The position Pr of the driven member 50 is monitored by comparing Pr with the final position Pe. When the current position Pr of the driven member 50 reaches the final position Pe, the position control unit 36 immediately stops the operation of the piezoelectric driving unit 10 and sets the current position Pr of the driven member 50 to the final position. Stopped in accordance with Pe. Accordingly, the position control unit 36 operates the piezoelectric driving unit 10 by position control so that the current position Pr of the driven member 50 becomes the final position Pe when the target position Pt (n) is the final position Pe. Yes.

  FIG. 7 is an explanatory diagram illustrating an example of the movement operation of the position Pr of the driven member 50 by the speed control of the speed control unit 34 and the position control of the position control unit 36. In FIG. 7, as an example of the movement locus of the target position (also referred to as “target locus”), the 0th target position Pt (0) as the start position Ps is the position P0, and the first target position Pt (1) is In the example, the position P1, the second target position Pt (2) is the position P2, and the third target position Pt (3) as the final position Pe is the position P3.

  When the first target position Pt (1) is instructed at the time (period timing) t0 in the first cycle, the speed control unit 34 determines that the first target position Pt from the above expressions (1) to (3). Based on (1) and the current position Pr (0) of the driven member 50, the first moving speed Vt (1) is obtained. At this time, the speed correction amount Vtc (1) given by the above equation (3) is zero. The obtained moving speed Vt (1) is supplied to the drive voltage generator 38. In the drive voltage generation unit 38, a drive voltage corresponding to the moving speed Vt (1) is generated and supplied to the piezoelectric drive unit 10. Thereby, in the cycle Ts from the cycle timing t0 of the first cycle to the cycle timing t1 of the second cycle, the piezoelectric driving unit 10 is driven with the drive voltage corresponding to the first moving speed Vt (1), and the target position The movement of the position Pr of the driven member 50 is executed so as to follow the movement locus (indicated by the solid line).

  Then, when the second target position Pt (2) is instructed at the cycle timing t1 of the second cycle, the second moving speed Vt (2) is obtained in the same manner as in the first cycle. The piezoelectric driving unit 10 is driven at a driving voltage corresponding to the moving speed Vt (2). However, as shown in the above equation (1), the second movement velocity Vt (2) is a planned movement velocity Vtr (2) (= [Pt] according to the planned movement velocity Vtr (n) of the above equation (2). (2) −Pt (1)] / Ts) and the speed correction amount Vtc (2) (= k · [= [Pt (1) −Pr) according to the speed correction amount Vtc (n) of the above equation (3). (1)] / Ts].

  Here, the actual movement locus (indicated by the alternate long and short dash line) of the position Pr of the driven member 50 may cause an error with respect to the target locus (indicated by the solid line). In the example of FIG. 7, the actual moving speed of the position Pr of the driven member 50 is slower than the set moving speed Vt (1), and the current position Pr of the driven member 50 at the cycle timing t1 of the second cycle. (1) does not reach the target position Pt (1). When such a position error occurs, the movement speed Vt (n) in each cycle is assumed to be only the planned movement speed Vtr (n) represented by the above expression (2) instead of the above expression (1). In this case, a position error occurs in each cycle, and the generated position errors are accumulated and increased in order, so that the operation locus deviates greatly from the target locus. Therefore, in the present embodiment, the moving speed Vt (n) is set by the planned moving speed Vtr (n) expressed by the above expression (2) and the above expression (3) as shown by the above expression (1). It is expressed as the sum of the speed correction amount Vtc (n) expressed. As a result, the moving speed Vt (n) is set so as to suppress the generated position error, so that the moving locus of the position Pr of the driven member 50 is brought close to the target locus as indicated by a one-dot chain line in FIG. be able to.

  Then, when the third target position Pt (3) is instructed at the cycle timing t2 of the third cycle, the third moving speed Vt (3) is obtained as in the second cycle, and the obtained third The piezoelectric driving unit 10 is driven with a driving voltage corresponding to the moving speed Vt (3). However, since the third target position Pt (3) is the final position Pe, the position controller 36 monitors whether or not the current position Pr of the driven member 50 reaches the final position Pe. Until the current position Pr reaches the final position Pe, the driving of the piezoelectric driving unit 10 with the driving voltage corresponding to the third moving speed Vt (3) is continued. Then, when the current position Pr of the driven member 50 reaches the final position Pe, the position control unit 36 instructs the drive voltage generation unit 38 to stop the operation, and the drive of the piezoelectric drive unit 10 is stopped. The current position Pr of the member 50 is stopped at the final position Pe.

  As described above, in the first embodiment, since the piezoelectric drive unit 10 is operated by speed control, it is suppressed that the operation and stop of the piezoelectric drive unit are repeated as compared with the conventional position control. The position of the driven member 50 can be moved smoothly. In the first embodiment, the position of the driven member 50 is set after the moving speed is set at the first cycle timing until the next moving speed is set at the second cycle timing after one cycle. Regardless of the operation, the operation of the piezoelectric driving unit 10 at the set moving speed is maintained. This can solve the problem that the operation and stop of the piezoelectric drive unit are repeated in each cycle as in the conventional position control, and smooth operation control is not performed. It is possible to solve the problem of generation of a stop sound due to the above.

  Further, since the position control is executed when the target position is the final position, the position of the driven member 50 can be accurately stopped at the final position. Furthermore, since the position control is executed only when the target position is the final position, the number of control loops for monitoring the current position of the driven member 50 is reduced, and the power consumption of the drive circuit is suppressed. This can save power.

B. Second embodiment:
FIG. 8 is an explanatory diagram showing the configuration of the speed control unit 34A and the position control unit 36 in the second embodiment. The speed control unit 34A omits the delay unit 342 of the speed control unit 34 (FIG. 6) of the first embodiment, and calculates the S / H unit 344A and the movement speed similar to the S / H unit 344 and the movement speed calculation unit 346. 346A is provided. The configuration of the position control unit 36 is the same as that of the position control unit 36 (FIG. 6) of the first embodiment. Since other configurations are the same as those in the first embodiment, illustration and description thereof are omitted.

  The S / H unit 344A of the speed control unit 34A samples (stores) input data of the target position Pt and the current position Pr of the driven member 50 at a cycle timing generated in the timing signal Sts at intervals of the cycle Ts. Hold. For example, at the cycle timing (first cycle timing) of the nth cycle Ts, the drive control unit 32 sets the nth target position (target position at the second cycle timing one cycle after the first cycle timing) Pt. When (n) is supplied (instructed), the data of the nth target position Pt (n) and the data of the current position Pr supplied from the encoder 40 are input to the S / H unit 344A. . In the S / H unit 344A, at the first cycle timing, the target position Pt (n) at the second cycle timing and the previous cycle target position Pt at the previous cycle timing one cycle before the first cycle timing. The current position Pr (n−1) corresponding to (n−1) is sampled and held.

The moving speed calculation unit 346A of the speed control unit 34 calculates a moving speed Vt (n) for moving the current position Pr of the driven member 50 to the target position Pt (n) during the period Ts, using the following equation (6). The moving speed Vt (n) determined by the calculation is supplied to the drive voltage generator 38.
Vt (n) = r · [Pt (n) −Pr (n−1)] / Ts (6)
Here, r is a correction coefficient. The correction coefficient r suppresses the error of the current position Pr (n−1) with respect to the previous cycle target position Pt (n−1), similarly to the correction coefficient k of the above equation (3), and the position of the driven member 50. For example, within the range of 0.8 or more and 1.2 or less, the actual movement is adjusted in advance so that the movement locus of Pr approaches the movement locus of the target position Pt.

  In addition, it is preferable that the restriction | limiting of the moving speed Vt (n) shown by said Formula (4) and (5) is applied similarly in this embodiment.

  Also in the second embodiment, since the piezoelectric drive unit 10 is operated by speed control, it is possible to suppress the operation and stop of the piezoelectric drive unit from being repeated as compared with the case where conventional position control is performed. The position of the member 50 can be moved smoothly. Also in the second embodiment, after the moving speed is set at the first cycle timing, until the next moving speed is set at the second cycle timing after one cycle, the driven member 50 Regardless of the position, the operation of the piezoelectric drive unit 10 at the set moving speed is maintained. This can solve the problem that the operation and stop of the piezoelectric drive unit are repeated in each cycle as in the conventional position control, and smooth operation control is not performed. It is possible to solve the problem of generation of a stop sound due to the above.

  Further, since the position control is executed when the target position is the final position, the position of the driven member 50 can be accurately stopped at the final position. Furthermore, since the position control is executed only when the target position is the final position, the number of control loops for monitoring the current position of the driven member 50 is reduced, and the power consumption of the drive circuit is suppressed. This can save power.

When the correction coefficient r in the above equation (6) is 1, the moving speed Vt (n) is expressed by the following equation (7).
Vt (n) = [Pt (n) −Pr (n−1)] Ts (7)
Here, in the moving speed Vt (n) in the first embodiment expressed by the above equations (1) to (3), when the correction coefficient k is 1, the above equations (2) and (3) Since Pt (n-1) is erased, the moving speed Vt (n) in the above equation (1) is the same as that in the above equation (7).

C. Other embodiments of the piezoelectric drive:
FIG. 9 is a cross-sectional view of a piezoelectric drive unit 10a as another embodiment of the present invention, and corresponds to FIG. 2B of the first embodiment. In the piezoelectric drive unit 10a, the piezoelectric vibrating body 100 is disposed on the diaphragm 200 in a state where the top and bottom of FIG. That is, here, the second electrode 150 is disposed close to the diaphragm 200 and the substrate 120 is disposed farthest from the diaphragm 200. In FIG. 9, as in FIG. 2B, wiring (or a wiring layer and an insulating layer) for electrical connection between the second electrodes 150a to 150e, the first electrode 130, and the second electrode Illustration of wirings (or wiring layers and insulating layers) for electrical connection between 150a to 150e and the drive circuit is omitted. This piezoelectric drive unit 10a can also achieve the same effect as that of the first embodiment.

  FIG. 10A is a plan view of a piezoelectric drive unit 10b as still another embodiment of the present invention, and corresponds to FIG. 2A of the above embodiment. 10A to 10C, for convenience of illustration, the connection part 220 and the attachment part 230 of the diaphragm 200 are not shown. In the piezoelectric driving unit 10b in FIG. 8A, the pair of second electrodes 150b and 150c are omitted. The piezoelectric driving unit 10b can also rotate the driven member (rotor) 50 in one direction z as shown in FIG. Since the same voltage is applied to the three second electrodes 150a, 150e, and 150d in FIG. 10A, these three second electrodes 150a, 150e, and 150d are formed as one continuous electrode layer. May be.

  FIG. 10B is a plan view of a piezoelectric driving unit 10c as still another embodiment of the present invention. In the piezoelectric driving unit 10c, the second electrode 150e at the center in FIG. 2A is omitted, and the other four second electrodes 150a, 150b, 150c, and 150d have a larger area than that in FIG. Is formed. This piezoelectric drive unit 10c can also achieve substantially the same effect as in the first embodiment.

  FIG. 10C is a plan view of a piezoelectric drive unit 10d as still another embodiment of the present invention. In the piezoelectric driving unit 10d, the four second electrodes 150a, 150b, 150c, and 150d in FIG. 2A are omitted, and one second electrode 150e is formed with a large area. The piezoelectric drive unit 10d only expands and contracts in the longitudinal direction, but can apply a large force from the contact member 20 to the driven member (not shown).

  As can be understood from FIG. 2 and FIGS. 10A to 10C, at least one electrode layer can be provided as the second electrode 150 of the piezoelectric vibrating body 100. However, if the second electrode 150 is provided at a diagonal position of the rectangular piezoelectric vibrator 100 as in the embodiment shown in FIGS. 2 and 10A and 10B, the piezoelectric vibrator 100 and The diaphragm 200 is preferable in that it can be deformed into a meandering shape that bends in the plane.

D. Embodiments of a device using a piezoelectric drive:
The piezoelectric drive device described above can apply a large force to the driven member by utilizing resonance, and can be applied to various devices. Piezoelectric driving devices include, for example, robots, electronic component conveying devices (IC handlers), medication pumps, clock calendar feeding devices, printing devices (for example, paper feeding mechanisms. However, in piezoelectric driving devices used for heads, diaphragms Therefore, it can be used as a driving device in various devices. Hereinafter, representative embodiments will be described.

  FIG. 11 is an explanatory diagram showing an example of a robot 2050 using the piezoelectric driving device 1000 described above. The robot 2050 includes a plurality of link portions 2012 (also referred to as “link members”) and an arm 2010 (“a” that includes a plurality of joint portions 2020 that connect the link portions 2012 in a rotatable or bendable state. It is also called “arm”. Each joint unit 2020 incorporates the piezoelectric drive unit 10 of the above-described piezoelectric drive unit 1000, and the joint unit 2020 can be rotated or bent by an arbitrary angle using the piezoelectric drive unit 10. It is. A robot hand 2000 is connected to the tip of the arm 2010. The robot hand 2000 includes a pair of grip portions 2003. The robot hand 2000 also has a built-in piezoelectric driving unit 10, and the piezoelectric driving unit 10 can be used to open and close the gripping unit 2003 to grip an object. The piezoelectric drive unit 10 is also provided between the robot hand 2000 and the arm 2010, and the robot hand 2000 can be rotated with respect to the arm 2010 using the piezoelectric drive unit 10. The drive circuit 30 that controls each piezoelectric drive unit 10 is included in a control circuit (not shown).

  FIG. 12 is an explanatory diagram of the wrist portion of the robot 2050 shown in FIG. The wrist joint portion 2020 sandwiches the wrist rotating portion 2022, and the wrist link portion 2012 is attached to the wrist rotating portion 2022 so as to be rotatable around the central axis O of the wrist rotating portion 2022. . The wrist rotating unit 2022 includes the piezoelectric driving unit 10, and the piezoelectric driving unit 10 rotates the wrist link unit 2012 and the robot hand 2000 around the central axis O. The robot hand 2000 is provided with a plurality of gripping units 2003. The proximal end portion of the gripping part 2003 is movable in the robot hand 2000, and the piezoelectric drive part 10 is mounted on the base part of the gripping part 2003. For this reason, by operating the piezoelectric drive unit 10, the gripping unit 2003 can be moved to grip the object. Further, by operating the piezoelectric drive unit 10 in the free mode, the arm 2010 and the wrist can be manually operated (so-called “teaching”), and the operation to be executed by the robot 2050 can be stored.

  The robot is not limited to a single-arm robot, and the piezoelectric drive unit 10 can be applied to a multi-arm robot having two or more arms. Here, in the wrist joint 2020 and the robot hand 2000, in addition to the piezoelectric drive unit 10, a power line for supplying power to various devices such as a force sensor and a gyro sensor, a signal line for transmitting a signal, and the like And requires a lot of wiring. Therefore, it is very difficult to arrange the wiring inside the joint portion 2020 and the robot hand 2000. However, since the piezoelectric drive unit 10 of the above-described embodiment can reduce the drive current as compared with a normal electric motor or a conventional piezoelectric drive device, the joint unit 2020 (particularly, the joint unit at the tip of the arm 2010) or a robot hand. Wiring can be arranged even in a small space such as 2000.

  FIG. 13 is an explanatory diagram showing an example of a liquid feed pump 2200 that uses the piezoelectric driving device 1000 described above. In the case 2230, the liquid feed pump 2200 includes a reservoir 2211, a tube 2212, a piezoelectric drive unit 10, a rotor 2222, a deceleration transmission mechanism 2223, a cam 2202, a plurality of fingers 2213, 2214, 2215, 2216, 2217, 2218, and 2219 are provided. The drive circuit 30 is not shown. The reservoir 2211 is a storage unit for storing a liquid to be transported. The tube 2212 is a tube for transporting the liquid sent out from the reservoir 2211. The contact member 20 of the piezoelectric drive unit 10 is provided in a state of being pressed against the side surface of the rotor 2222, and the piezoelectric drive unit 10 rotationally drives the rotor 2222. The rotational force of the rotor 2222 is transmitted to the cam 2202 via the deceleration transmission mechanism 2223. Fingers 2213 to 2219 are members for closing the tube 2212. When the cam 2202 rotates, the fingers 2213 to 2219 are sequentially pushed outward in the radial direction by the protrusion 2202A of the cam 2202. The fingers 2213 to 2219 close the tube 2212 in order from the upstream side in the transport direction (reservoir 2211 side). Thereby, the liquid in the tube 2212 is transported to the downstream side in order. In this way, it is possible to realize a small liquid feed pump 2200 that can deliver an extremely small amount with high accuracy and that is small. In addition, arrangement | positioning of each member is not restricted to what was illustrated. Further, a member such as a finger may not be provided, and a ball or the like provided on the rotor 2222 may close the tube 2212. The liquid feed pump 2200 as described above can be used for a medication device that administers a drug solution such as insulin to the human body. Here, by using the piezoelectric driving device 1000 of the above-described embodiment, the driving current becomes smaller than that of the conventional piezoelectric driving device, so that the power consumption of the dosing device can be suppressed. Therefore, it is particularly effective when the medication apparatus is battery-driven.

E. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) In the above embodiment, the first electrode 130, the piezoelectric body 140, and the second electrode 150 are formed on the substrate 120. However, the substrate 120 is omitted and the first electrode is formed on the vibration plate 200. 130, the piezoelectric body 140, and the second electrode 150 may be formed.

(2) In the above embodiment, one piezoelectric vibrating body 100 is provided on each of both surfaces of the vibration plate 200, but one of the piezoelectric vibrating bodies 100 can be omitted. However, providing the piezoelectric vibrating bodies 100 on both surfaces of the diaphragm 200 is preferable in that it is easier to deform the diaphragm 200 into a meandering shape bent in the plane.

(3) In each of the above embodiments, the piezoelectric element that uses a piezoelectric body formed by a film forming process has been described as an example. However, the piezoelectric body may be a bulk piezoelectric body.

(4) In the above-described embodiment, the configuration in which the vibration body portion 210 is supported by the connection portions 220 extending from the left and right long sides of the vibration body portion 210 so as to be able to vibrate is described as an example. The position and number are not limited to this, and various arrangement positions and numbers can be adopted. For example, a connection part may be provided only on one side along the longitudinal direction, and the vibrating body part 210 may be supported in a cantilever state. In addition, a connection portion may be provided on the short side of the vibrating body portion 210 opposite to the contact member 20 to support the vibrating body portion 210 in a cantilever state.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above-described effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10, 10a, 10b, 10c, 10d ... Piezoelectric drive part 12 ... Tube 20 ... Contact member 30 ... Drive circuit 32 ... Drive control part 34, 34A ... Speed control part 36, 36A ... Position control part 38 ... Drive voltage generation part 40 ... Encoder 50 ... Driven member (rotor)
51 ... Center of driven member 100 ... Piezoelectric vibrator 110a, 110b, 110c, 110d, 110e ... Piezoelectric element 120 ... Substrate 125 ... Insulating layer 130 ... First electrode 140 ... Piezoelectric body 150, 150a, 150b, 150c, 150d, 150e ... second electrode 151,152 ... wiring 200 ... diaphragm 201 ... center of vibrating body part (vibrating plate) 202 ... center line 210 ... vibrating body part 220 ... connecting part 230 ... mounting part 240 ... screws 310, 312, 314 , 320 ... Wiring 342 ... Delay part 344, 344A ... Sample hold part (S / H part)
346, 346A ... Movement speed calculation unit 364 ... Sample hold unit (S / H unit)
366 ... Position comparison unit 1000 ... Piezoelectric drive device 2000 ... Robot hand 2003 ... Holding unit 2010 ... Arm 2012 ... Link unit 2020 ... Joint unit 2022 ... Wrist rotation unit 2050 ... Robot 2200 ... Liquid feed pump 2202 ... Cam 2202A ... Protrusion unit 2211 ... Reservoir 2212 ... Tube 2213 ... Finger 2222 ... Rotor 2223 ... Deceleration transmission mechanism 2230 ... Case

Claims (6)

A piezoelectric drive for driving the driven member;
A drive circuit for driving the piezoelectric drive unit;
With
The drive circuit is a piezoelectric drive device that operates the piezoelectric drive unit by speed control. The piezoelectric drive device according to claim 1,
The drive circuit is
When moving the position of the driven member from the first position to the second position in accordance with a movement trajectory based on the target position of the driven member that is instructed at regular intervals,
When the target position at the second cycle timing one cycle after the first cycle timing is instructed at the first cycle timing, the target position and the current position of the driven member at the first cycle timing And determining a moving speed to the target position, and executing speed control for operating the piezoelectric driving unit at the determined moving speed from the first cycle timing to the second cycle timing. Piezoelectric drive device. The piezoelectric drive device according to claim 2,
The drive circuit calculates a planned moving speed obtained based on the previous cycle target position and the target position, which are instructed at the previous cycle timing one cycle before the first cycle timing, from the previous cycle target position and the target cycle. A piezoelectric driving device that determines the moving speed to the target position by correcting based on a current position. The piezoelectric drive device according to claim 2 or 3, wherein
When the target position is the second position, the drive circuit performs position control to stop the piezoelectric drive unit when the position of the driven member reaches the second position. Drive device. A plurality of link parts;
A joint part connecting the plurality of link parts;
The piezoelectric driving device according to any one of claims 1 to 4, wherein the plurality of link portions are rotated by the joint portion using the driven member.
Robot equipped with. A driving method of a piezoelectric driving device having a piezoelectric driving unit for driving a driven member,
A driving method of a piezoelectric driving device, wherein the piezoelectric driving unit is operated by speed control.

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