JP4134075B2 - Sonic levitation device - Google Patents

Description

The present invention relates to a resonance frequency detection method of acoustic levitation device and acoustic levitation devices, and particularly relates to acoustic levitation equipment levitate an object using a radiation pressure of the ultrasonic waves by vibrating the vibrator long. In this specification, the term “long vibrator” means that the length of the vibrator is not less than 10 wavelengths of the vibration wavelength.

  A vibrator on the excitation side (excitation side) is provided at one end of the long vibrator, and a vibrator on the receiving side is provided at the other end. A traveling wave is generated in the vibrator, and the vibrator is generated by the radiation pressure. An object levitation conveyance device (sonic levitation device) that conveys an object in a state where the object is levitated on the surface of the surface has been proposed (for example, see Patent Document 1). This apparatus uses a long flat plate-like vibrating body, and an excitation-side vibrator is provided at one end of the vibrating body and a receiving-side vibrator is provided at the other end. Then, the vibrator on the excitation side is excited by being connected to an oscillator, a traveling wave is generated in the vibrating body, and the object is floated on the surface of the vibrating body by the radiation pressure and conveyed.

In the object levitating and conveying apparatus of Patent Document 1, a Langevin type vibrator using a piezoelectric element (piezo element) is used as a vibrator on the excitation side. Then, the vibrator is vibrated with the required strength (amplitude) by exciting the vibrator at a resonance frequency that maximizes the receiving side amplitude in the fringe mode, and the vibration state for detecting the receiving side vibration state. The oscillator is controlled by feeding back a signal from the detection means. As the vibration state detecting means, a voltage sensor for detecting the output voltage of the piezoelectric element constituting the receiving-side vibrator is provided. The control is performed so that the voltage on the receiving side is the maximum or equal to or higher than a preset value, and is substantially constant current control.
JP 2003-126778 A (paragraphs [0020], [0021], [0024], FIG. 1 of the specification)

  When the exciting side and the receiving side of the vibrating body are separated like a long plate, even if the vibrating body is vibrated satisfactorily on the exciting side, vibration may not be satisfactorily performed on the receiving side. In addition, since a long vibrating body has a plurality of eigenvalues of the resonance frequency, even if it vibrates in a desired mode (for example, a fringe mode) on the excitation side, it vibrates in a state other than the desired mode on the receiving side. There is. In particular, when a standing wave is generated in a vibrating body, it is preferable to excite at a resonance point. However, when a traveling wave is generated, a predetermined phase difference between the resonance point and the receiving side is not the resonance point. Therefore, it is necessary to feed back the vibration state on the receiving side.

  In the apparatus of Patent Document 1, the vibrator is excited at a resonance frequency that maximizes the receiving-side amplitude in the fringe mode. For this purpose, prior to the normal operation of the apparatus, it is necessary to perform a frequency sweep that sweeps the output of the oscillator over the entire frequency range set in advance, and to detect the resonance frequency that maximizes the receiving side amplitude in the fringe mode. In the conventional apparatus, since the oscillator is controlled by constant current control, the frequency sweep is also performed by constant current control. However, when frequency sweep is performed with constant current control, vibration occurs at a position slightly deviated from the resonance point. As a result, the detection accuracy of the resonance frequency is low, and fine adjustment is necessary to efficiently vibrate the vibrating body. Become. Also, depending on conditions such as the length and load of the vibrating body, when the vibrating body is excited at a resonance frequency that maximizes the receiving-side amplitude in the fringe mode, the end of the vibrating body (the vibrator of the vibrating body) There may be a case where the vibration does not vibrate uniformly from the fixed part to the horn to the end of the vibrating body.

The present invention was made in view of the above problems, purpose of that can accurately detect the resonance frequency at the time of exciting the vibrating member elongated in the excitation side of the transducer, from the conventional apparatus An object of the present invention is to provide a sonic levitation device capable of efficiently vibrating a vibrating body .

In order to achieve the first object, the invention according to claim 1 includes constant voltage control means for performing constant voltage control of an oscillator that excites an excitation-side vibrator connected to one end of a long vibrator, and Frequency sweeping means for sweeping the output of the oscillator with constant voltage control over the entire frequency range set in advance. Further, a vibration state detection means for detecting an output voltage oscillator reception side that is connected to the other end of the vibrator is output, the frequency of the output peak of the vibration state detection means at the time of the frequency sweep by said frequency sweep means at least the supply voltage supplied to the excitation side of the vibrator at the time the frequency sweep by said frequency sweep means with vibrating body stores the resonance frequencies of large amplitude in the resonance frequency and the second becomes the maximum amplitude phase of the And a storage means for storing the phase of the output voltage output by the receiving-side vibrator, and a phase difference between the phase of the supply voltage and the phase of the output voltage stored in the storage means. Of the resonance frequency stored in the storage means and the determination means for determining the vibration mode, the determination means determines that the vibrating body vibrates in the fringe mode. The amplitude of the vibration member out of the frequency and a selection means for selecting a resonance frequency of the reference resonant frequency becomes maximum.

In the present invention, by sweeping the output of the oscillator over the entire frequency range set in advance by the frequency sweep means, it is possible to accurately detect all the resonance frequencies within the frequency range. At least the amplitude of the vibration member in the reception side of the vibrating body becomes large amplitude in the resonance frequency and the second becomes the maximum resonance frequency is stored in the storage means. Therefore, when the apparatus is normally operated, when the condition that the amplitude on the receiving side of the vibrating body is maximized is not the condition for exciting the vibrating body in an optimum state, by exciting the second resonant frequency as a reference, by vibrating the vibrating body in an appropriate state can and Turkey.

  According to a second aspect of the present invention, in the first aspect of the invention, there is provided constant current control means for controlling the oscillator at a constant current, and the oscillator is controlled at a constant current during normal operation. Here, the “normal operation” means a case where the vibrating body is excited in order to float or lift the object.

  In the present invention, by driving the oscillator by constant voltage control, it is possible to accurately detect the resonance frequency when the long vibrating body is excited by the vibrator on the excitation side. Further, since the oscillator is controlled at a constant current during normal operation, it becomes easy to drive the vibrator with a constant amplitude.

  According to a third aspect of the present invention, in the second aspect of the present invention, the constant current control means and the constant voltage control means are configured by the same circuit. In this invention, compared with the case where a constant current control means and a constant voltage control means are each made into an independent circuit structure, the increase in the physique and weight of an apparatus can be suppressed, and manufacturing cost can be reduced.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the storage means further stores a value corresponding to the amplitude of the vibrating body at each resonance frequency. To do . Here, the “value corresponding to the amplitude” is not limited to the value of the detection signal output from the vibration state detection unit itself, but is an amplitude value calculated from the value of the detection signal or a value obtained by multiplying the amplitude value by a coefficient. Etc.

  In this invention, since the resonance frequency and the value corresponding to the amplitude of the vibrating body at the resonance frequency are stored in the storage means, the excitation condition of the vibrating body that is in an optimal vibration state is selected based on the information. It becomes easy.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, at least a resonance frequency of the vibrating body and a vibration mode of the vibrating body determined by the determining means. A display device for displaying is provided. Therefore, according to the present invention, the resonance frequency and vibration mode of the vibrating body can be confirmed on the display device, and it can be easily confirmed whether or not the device is operated in a desired state.

  The invention according to a sixth aspect is the invention according to any one of the first to fifth aspects, wherein the vibrating body is fixed to a horn, and an end portion of the vibrating body is fixed to the horn. Vibration detecting means for detecting side vibration is provided. In this invention, it can be confirmed whether or not the vibrating body vibrates to both ends thereof, and the excitation condition is changed to prevent the excitation from continuing in a state different from the state in which the vibrating body vibrates to both ends. Easy to do.

  According to the present invention, in the sonic levitation device, it is possible to accurately detect the resonance frequency when a long vibrating body is excited by the vibrator on the excitation side.

(First embodiment)
A first embodiment in which the present invention is embodied in an object levitating and conveying apparatus will be described below with reference to FIGS. FIG. 1 is a schematic perspective view of an object levitation conveyance device, FIG. 2 is a schematic side view of the object levitation conveyance device, and FIG. 3 is a block circuit diagram of a driving power source.

  As shown in FIGS. 1 and 2, the object levitation transfer device 11 as a sonic levitation device includes a diaphragm 12 as a long vibrating body. The diaphragm 12 is formed in a rectangular flat plate shape. An excitation-side vibrator 13 is provided on one end side (the left end side in FIGS. 1 and 2) of the diaphragm 12, and a receiving-side vibrator 14 is provided on the other end side. It is concluded by. The horn 15 is formed in a flat and substantially rectangular parallelepiped shape, and is attached to the diaphragm 12 in a state orthogonal to the longitudinal direction at both ends in the longitudinal direction.

  Each horn 15 is fixed to each vibrator 13 and 14 on the surface opposite to the surface to which the diaphragm 12 is fastened. That is, the horn 15 constitutes a part of the vibrator 13. The front end surface of the horn 15 is formed on a plane orthogonal to the axial direction of the vibrators 13 and 14, and the central axes of the horn 15 and the vibrators 13 and 14 are arranged in a state extending in the vertical direction.

  So-called Langevin-type vibrators are used as the vibrators 13 and 14 and are provided with a pair of ring-shaped piezoelectric elements 17a and 17b. A ring-shaped electrode plate 18 is disposed between the piezoelectric elements 17a and 17b, and metal blocks 19a and 19b that are in contact with the surface of the piezoelectric elements 17a and 17b opposite to the side in contact with the electrode plate 18 are attached by bolts (not shown). The vibrators 13 and 14 are configured by tightening and fixing. The bolt is screwed into a screw hole (not shown) formed in the metal block 19a from the metal block 19b side. Both metal blocks 19a and 19b are in a state of being electrically connected to each other via bolts.

  As shown in FIG. 2, a flange 20 is formed at the upper end of the metal block 19 a, and the metal block 19 a is fitted into a hole (not shown) formed in the base plate 21 with a bolt (not shown) by means of a bolt (not shown). The base plate 21 is fixed.

  The vibrator 13 for exciting the horn 15 fastened to the excitation side of the diaphragm 12 is connected to a power supply device 23 having an oscillator 22. The electrode plate 18 is connected to the oscillator 22 via the wiring 24a, and the ground terminal of the oscillator 22 is connected to the metal block 19b via the wiring 24b.

  Piezoelectric elements 17a and 17b as energy conversion elements of the vibrator 14 fastened to the receiving side of the diaphragm 12 are connected to a load circuit 25 as an energy conversion means including a resistor R and a coil L, an electrode plate 18 and a metal. Each is connected via a block 19b. The vibrator 14 is equipped with a voltage sensor 26 that detects a voltage generated in the piezo elements 17a and 17b. The voltage sensor 26 constitutes vibration state detection means for outputting a detection signal corresponding to the vibration state on the wave receiving side of the diaphragm 12.

  As shown in FIG. 3, the power supply device 23 includes a DC constant voltage generation circuit 27, an inverter circuit 28, a control device 29, and a current sensor 30. The DC constant voltage generation circuit 27 is configured to be able to convert input power into a predetermined DC constant voltage, and is configured to be able to set an upper limit value of the conversion voltage. The inverter circuit 28 receives the DC voltage output from the DC constant voltage generation circuit 27 and converts it into AC. The inverter circuit 28 is configured so that the output voltage can be changed by a transformer, for example. The current sensor 30 detects the amount of current output from the inverter circuit 28 and flowing through the load, that is, the vibrator 13. The inverter circuit 28 constitutes the oscillator 22.

  In this embodiment, a constant voltage control means for constant voltage control of the oscillator 22 that excites the vibrator 13 on the excitation side and a constant current control means for constant current control of the oscillator 22 are connected to the DC constant voltage generation circuit 27. And the control apparatus 29 comprises. Further, the control device 29 constitutes frequency sweeping means for sweeping the output of the oscillator 22 by constant voltage control over the entire preset frequency range.

  The control device 29 includes a CPU (central processing unit) 31 and a memory 32 as storage means. The voltage sensor 26 and the current sensor 30 are connected to the CPU 31 via an A / D converter and an interface (both not shown). The control device 29 performs constant current control so as to have a set current value during normal operation. Further, the control device 29 is configured to detect the resonance frequency of the diaphragm 12 prior to normal operation. The control device 29 sweeps the output of the oscillator 22 by constant voltage control over the entire frequency range set in advance, and based on the detection signal of the voltage sensor 26, the voltage corresponding to the resonance state on the receiving side of the diaphragm 12. Resonance frequency is detected by detecting the peak.

  When performing the constant current control, the control device 29 inputs a detection signal of the current sensor 30 and, if the detection signal is smaller than the set current value, a command signal for increasing the output voltage to the DC constant voltage generation circuit 27. And the output current value of the inverter circuit 28 is increased. Conversely, if the detection signal of the current sensor 30 is larger than the set current value, a command signal for decreasing the output voltage is output to the DC constant voltage generation circuit 27 to decrease the output current value of the inverter circuit 28.

  When performing voltage control, the control device 29 restricts the upper limit of the output voltage set value in the DC constant voltage generation circuit 27 (for example, restricts it to 10% of the maximum value), and increases the set value of the output constant current of the inverter circuit 28. (For example, 90% of the maximum value). If the control is performed in this state, the output current of the inverter circuit 28 is controlled to the set constant current value and the output voltage of the DC constant voltage generation circuit 27 is increased, but the voltage upper limit setting is narrowed down. , Take restrictions. As a result, the output of the DC constant voltage generation circuit 27 becomes constant at the voltage upper limit set value, and constant voltage control is performed.

  The memory 32 stores a map indicating the relationship between the voltage upper limit setting value when performing constant voltage control and the current supplied to the load, and an appropriate voltage upper limit setting value when performing constant voltage control with the load. Has been changed. The map is obtained by conducting a test in advance.

  The control device 29 stores in the memory 32 information detected during a frequency sweep performed prior to normal operation. As information, at least the peak frequency corresponding to the maximum amplitude of the diaphragm 12 among the output peaks of the voltage sensor 26 and the peak frequency corresponding to the second largest amplitude, that is, the maximum amplitude of the diaphragm 12 among the resonance frequencies, and There is a resonance frequency corresponding to the second largest amplitude and a value corresponding to the amplitude of the diaphragm 12 at the resonance frequency. In this embodiment, the voltage V2 output from the voltage sensor 26 is stored as a value corresponding to the amplitude. The control device 29 stores all the resonance frequencies and the corresponding voltage V2. The information includes the phase of the voltage V1 supplied to the excitation-side vibrator 13 and the phase of the voltage V2 output from the voltage sensor 26 based on the vibration of the receiving-side vibrator 14.

  As shown in FIG. 4, the control device 29 includes a communication port 33, and a control monitor 35 as a display device is connected to the control device 29 via a communication cable 34 connected to the communication port 33. The control monitor 35 includes a microcomputer (not shown), and displays information stored in the memory 32 of the control device 29 and information obtained by processing the information on the screen. The displayed information includes at least the resonance frequency of the diaphragm 12, the vibration mode when the diaphragm 12 is excited at the resonance frequency, the amplitude of the diaphragm 12, the phase difference between the voltage V1 and the voltage V2, and the like. There is.

  Since the vibration mode, that is, whether the diaphragm 12 vibrates in the stripe mode or the lattice mode can be determined from the phase difference between the voltage V1 and the voltage V2, the control monitor 35 is connected to the control device via the communication cable 34. Based on the phase information of the voltage V1 and the voltage V2 obtained from 29, it is determined whether the mode is the stripe mode or the lattice mode, and the vibration mode is displayed.

  The screen shown in FIG. 4 shows an example of a display screen at the time of constant voltage control for resonance frequency detection. In the screen of FIG. 4, a graph with the voltage V2 on the vertical axis and the frequency on the horizontal axis, and the frequency at the peak position of the graph, that is, the value of the resonance frequency are displayed in characters. Further, when all the resonance frequencies cannot be displayed on the graph at the same time, the resonance frequency is divided into a plurality of times or displayed by scrolling the screen. In addition, regarding the portion of the resonance frequency that causes the vibration in the stripe mode, a display for distinguishing it is made. As an example of the display for distinguishing the fringe mode, there are a method of displaying the peak of the resonance frequency of the fringe mode in a different color, or shading a range of frequencies that can vibrate in the fringe mode around the peak.

  During normal operation, the control monitor 35 displays information on the vibration mode, the resonance frequency, the value corresponding to the amplitude of the diaphragm 12, and the phase difference between the voltage V1 and the voltage V2 in the operation state. During constant voltage control for detecting the resonance frequency, the control monitor 35 displays all detected resonance frequencies, the amplitude of the diaphragm 12, the vibration mode, and the phase difference between the voltage V1 and the voltage V2.

  As the excitation condition during normal operation, the control device 29 resonates with the maximum amplitude of the diaphragm 12 among the frequencies at which the diaphragm 12 vibrates in the stripe mode among the resonance frequencies detected by the resonance frequency detection process. The oscillator 22 is controlled at a constant current so that the vibrator 13 is excited by selecting an excitation condition for the frequency. However, the operator can instruct the control device 29 to excite the vibrator 13 at the resonance frequency selected from all the resonance frequencies by selecting the resonance frequency displayed on the control monitor 35. .

Next, the operation of the object levitation transfer device 11 configured as described above will be described.
Prior to normal operation, the resonance frequency is detected. The control device 29 sweeps the output of the oscillator 22 by constant voltage control over the entire preset frequency range, and detects all resonance frequencies. Then, all the detected resonance frequency values, values corresponding to the amplitude of the diaphragm 12 at each resonance frequency, and the phases of the voltages V1 and V2 are stored in the memory 32. Then, the detected resonance frequency, the vibration mode at each resonance frequency, and the phase difference between the voltage V2, the voltage V1, and the voltage V2 as values corresponding to the amplitude of the diaphragm 12 are displayed on the control monitor 35.

  The operator confirms the display on the control monitor 35 and selects the resonance frequency for normal operation. Then, normal operation is performed at the selected resonance frequency. When the operator does not select the resonance frequency, the control device 29 excites the vibration frequency at which the vibration plate 12 has the maximum resonance frequency among the detected resonance frequencies at which the vibration plate 12 vibrates in the stripe mode. Select a condition and perform normal operation under that excitation condition.

  In normal operation, the oscillator 22 is controlled by constant current control. The oscillator 22 is driven by a control signal from the control device 29, and the vibrator 13 is excited at a frequency in the vicinity of the selected resonance frequency (for example, around 20 kHz). When the vibrator 13 is excited, the horn 15 is longitudinally vibrated, and the diaphragm 12 is excited via the horn 15 to perform flexural vibration. The object M is levitated from the surface of the diaphragm 12 by the radiation pressure of the sound wave radiated from the diaphragm 12. The levitation distance is several tens to several hundreds μm.

  The vibration of the diaphragm 12 is transmitted to the receiving-side vibrator 14, and the vibration energy, which is mechanical energy, is converted into electric energy by the piezoelectric elements 17 a and 17 b constituting the vibrator 14. This electrical energy is converted into Joule heat by the resistance R of the load circuit 25 and is dissipated. Therefore, the vibration wave generated in the diaphragm 12 becomes a traveling wave that travels in one direction from the excitation side to the reception side (in this embodiment, a traveling wave that travels from the vibrator 13 side to the vibrator 14 side), The object M is conveyed in a floating state from the excitation side of the diaphragm 12 to the wave receiving side.

  When the control device 29 confirms that the object M has reached the vicinity of the stop position based on a detection signal from an object detection sensor (not shown), the control device 29 changes the output of the oscillator 22 to a state in which the diaphragm 12 generates a standing wave. Then, the object M is decelerated and stopped in the levitation state.

  The control device 29 controls the output of the oscillator 22 so that a traveling wave from the vibrator 13 side toward the vibrator 14 side is generated on the diaphragm 12. The control device 29 is a phase difference (for example, a phase difference between the voltage V1 input to the excitation-side vibrator 13 and the voltage V2 output from the reception-side vibrator 14 is likely to generate a traveling wave in which the phase difference is set in advance. 90 degrees), and the output of the oscillator 22 is controlled so that the output voltage of the receiving-side vibrator 14 becomes a predetermined value or more. The output voltage and phase of the receiving-side vibrator 14 are detected by the output signal of the voltage sensor 26.

  In the vibrator 13 using a piezoelectric element, it is necessary to excite the vibrator 13 at a resonance frequency in order to vibrate efficiently in a state where the diaphragm 12 generates a standing wave. On the other hand, in order to vibrate the diaphragm 12 in a state in which traveling waves are efficiently generated, it is preferable to excite the vibrator 13 at a frequency slightly shifted from the resonance frequency instead of the resonance frequency. The control device 29 then applies voltages V1, V1 of the excitation-side and receiving-side vibrators 13 and 14 to efficiently generate a traveling wave set based on the resonance frequency selected from the plurality of resonance frequencies. The oscillator 22 is controlled to excite the vibrator 13 with the phase difference of V2 and the frequency of the vibrator 13. When the environment of the object levitation transfer device 11 changes, the resonance frequency and the phase difference between the voltage V1 and the voltage V2 that are appropriate when the resonance frequency is detected may deviate from the appropriate excitation conditions.

  Since the control device 29 always detects the vibration state of the receiving-side vibrator 14 by inputting the output from the voltage sensor 26, the vibration state can be accurately grasped from the phase and magnitude of the voltage V2. . When the vibration state of the vibrator 14 is weakened or the like, the phase of the voltage V1 output from the oscillator 22 is changed or the constant current control is performed. Increase the set current value.

When it is confirmed from the output of the voltage sensor 26 that the vibration state of the vibrator 14 has returned to a state in which a traveling wave is efficiently generated, the driving of the oscillator 22 is continued under that condition.
This embodiment has the following effects.

  (1) Constant voltage control means (DC constant voltage generation circuit 27 and control device 29) for constant voltage control of the oscillator 22 for exciting the vibrator 13 on the excitation side connected to one end of the long diaphragm 12; Frequency sweeping means (control device 29) for sweeping the output of the output by constant voltage control over the entire preset frequency range. In addition, vibration state detection means (voltage sensor 26) that outputs a detection signal (voltage V2) corresponding to the vibration state on the wave receiving side of the diaphragm 12 is provided. Therefore, by sweeping the output of the oscillator 22 by constant voltage control over the entire frequency range set in advance under the control of the control device 29, all resonance frequencies within the frequency range can be detected accurately. Further, even if the vibration state on the receiving side changes due to the fluctuation of the load of the vibration system due to the difference in the weight of the object M or the like, the excitation condition of the vibrator 13 on the excitation side is set based on the accurate resonance frequency. Can do.

  (2) All resonance frequencies detected during the frequency sweep and values corresponding to the amplitude of the diaphragm 12 at each resonance frequency are stored in the memory 32. Therefore, when the object levitation transfer device 11 is normally operated, the diaphragm 12 is in an appropriate state when the condition that the amplitude on the wave receiving side of the diaphragm 12 is maximum is not the condition for exciting the diaphragm 12 in an optimum state. It is possible to easily change to the excitation conditions for vibration.

  (3) Constant current control means (a DC constant voltage generation circuit 27 and a control device 29) for controlling the oscillator 22 with constant current is provided, and the oscillator 22 is controlled with constant current during normal operation. Accordingly, during normal operation, the oscillator 22 is controlled at a constant current, so that the diaphragm 12 can be easily driven with a constant amplitude.

  (4) The constant current control means and the constant voltage control means are composed of the same circuit. Therefore, as compared with the case where the constant current control unit and the constant voltage control unit have independent circuit configurations, an increase in the size and weight of the apparatus can be suppressed, and the manufacturing cost can be reduced.

  (5) Since at least the resonance frequency and the value corresponding to the amplitude of the diaphragm 12 at the resonance frequency are stored in the memory 32, the optimum value based on the information is stored. It becomes easy to select the excitation condition of the diaphragm 12 which will be in a vibration state.

  (6) A control monitor 35 that displays at least the resonance frequency and vibration mode of the diaphragm 12 is provided. Therefore, the operator can confirm the resonance frequency and vibration mode of the diaphragm 12 on the control monitor 35, and can easily confirm whether or not the object levitation transfer device 11 is operated in a desired state.

  (7) During normal operation, the control monitor 35 displays information on the vibration mode, the resonance frequency, the amplitude of the diaphragm 12 and the phase difference between the voltage V1 and the voltage V2 in the operation state. Therefore, the operator can easily determine whether or not the current excitation condition is in an appropriate state when the operating environment changes.

  (8) During the constant voltage control for detecting the resonance frequency, the control monitor 35 displays all the detected resonance frequencies, values corresponding to the amplitude of the diaphragm 12, the vibration mode, and the phase difference between the voltage V1 and the voltage V2. To do. Therefore, the operator can easily select the resonance frequency corresponding to the appropriate excitation condition based on the display.

  (9) The control device 29 excites the vibrator 13 so as to generate a traveling wave in the long diaphragm 12. At this time, since the vibration state of the vibrator 14 on the receiving side is detected by the voltage sensor 26 and fed back, the control device 29 causes the phase difference between the vibration on the excitation side and the receiving side to generate a traveling wave. It is possible to check whether the state is appropriate.

  (10) Since the voltage sensor 26 for detecting the voltage V2 output from the energy conversion elements (piezo elements 17a and 17b) is used as the vibration state detection means for detecting the vibration state of the receiving-side vibrator 14. The vibration state of the receiving-side vibrator 14 can be easily detected.

  (11) As the excitation-side and receiving-side vibrators 13 and 14, vibrators having the same configuration including the piezoelectric elements 17a and 17b are used. Therefore, it is easy to electrically detect the vibration state of the receiving-side vibrator 14. Further, by connecting the load circuit 25, it becomes easy to generate a traveling wave stably.

  (12) The vibration energy, which is mechanical energy, is converted into electrical energy by the piezoelectric elements 17 a and 17 b constituting the vibrator 14 on the receiving side, and this electrical energy is converted into Joule heat by the resistance R of the load circuit 25. Dissipated. Accordingly, a traveling wave from the excitation side toward the reception side can be easily generated as compared with a configuration in which the vibration energy is not consumed by the load circuit 25.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. This embodiment is different from the first embodiment in that vibration detecting means is provided at both ends of the diaphragm 12. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In order to detect the vibration on the end side of the diaphragm 12 from the fixed position with respect to the horn 15, vibration pickups 36 a and 36 b are provided at both ends of the diaphragm 12 as vibration detecting means on the lower surface on the end side from the fixed position on the horn 15. It is fixed. The vibration pickup 36 a is fixed to the excitation side end of the diaphragm 12, and the vibration pickup 36 b is fixed to the reception side end of the diaphragm 12. Detection signals from the vibration pickups 36 a and 36 b are input to the control device 29.

  When performing frequency sweeping with constant voltage control to detect the resonance frequency, the control device 29, in addition to the same information as in the first embodiment, the detection information of the vibration pickups 36a and 36b, that is, the vibration Values corresponding to the amplitudes at both ends of the plate 12 are also stored in the memory 32. In addition to the detected resonance frequency, the vibration mode at each resonance frequency, the value corresponding to the amplitude of the diaphragm 12, and the phase difference between the voltage V <b> 1 and the voltage V <b> 2, the control monitor 35 includes the end of the diaphragm 12. A value corresponding to the amplitude as the vibration state is displayed. The output voltage V3 of the vibration pickup 36a and the output voltage V4 of the vibration pickup 36b are displayed as values corresponding to the amplitude as the vibration state at the end of the diaphragm 12.

  When the diaphragm 12 is vibrated at a resonance frequency that maximizes the amplitude on the receiving side in the stripe mode, the diaphragm 12 may not necessarily vibrate uniformly to the end of the diaphragm 12. The vibration state of the vibrator 14 on the receiving side of the diaphragm 12 accurately reflects the vibration between the parts fixed to the horn 15 of the diaphragm 12, but the free end side from the part fixed to the horn 15. This is not accurately reflected. Therefore, simply monitoring the value of the voltage V <b> 2 output from the voltage sensor 26 is not reliable for grasping the vibration state of the entire diaphragm 12. However, in this embodiment, it is possible to reliably determine whether or not the vibrations are uniformly vibrated up to the end of the diaphragm 12 by the detection signals of the vibration pickups 36a and 36b.

Therefore, the second embodiment has the following effects in addition to the same effects as the effects (1) to (12) of the first embodiment.
(13) A vibration detecting means (vibration pickups 36a and 36b) for detecting the vibration on the end side from the fixed position of the diaphragm 12 with respect to the horn 15 is provided. Therefore, it can be confirmed whether or not the diaphragm 12 vibrates to both ends thereof, and the excitation condition is changed so as to prevent the excitation from continuing in a state different from the state in which the diaphragm 12 vibrates to both ends. Easy to do. Further, since the vibrator 13 can be excited under the condition of efficiently and stably vibrating to the end portion of the diaphragm 12, the object M is transported by connecting a plurality of object levitation transport devices 11 in series. At this time, the object M can be stably levitated also at the connecting portion from the diaphragm 12 on the upstream side in the conveying direction to the diaphragm 12 on the downstream side.

(14) Since the vibration pickups 36a and 36b fixed to the diaphragm 12 are used as the vibration detecting means, vibration can be detected with high accuracy with a compact configuration.
The embodiment is not limited to the above, and may be configured as follows, for example.

  A voltage sensor 26 that detects voltages generated in the piezo elements 17a and 17b constituting the vibrator 14 on the receiving side as vibration state detecting means for outputting a detection signal corresponding to the vibration state on the receiving side of the diaphragm 12. Instead of this, a vibration pickup may be provided on the wave receiving side of the diaphragm 12, and the detection signal may be substituted for the voltage V2.

  The vibration state detecting means for outputting a detection signal corresponding to the vibration state on the receiving side of the diaphragm 12 indicates that the receiving side of the diaphragm 12 is vibrating when the excitation side vibrator 13 is excited. What is necessary is just to be able to detect, and it is not limited to the configuration in which the vibration on the receiving side of the diaphragm 12 is directly detected, but may be the configuration in which the vibration at the location that vibrates when the receiving side vibrates is detected. Therefore, when the vibration pickup is used as the vibration state detection means, the attachment position is not limited to the wave receiving side of the diaphragm 12 but may be attached to a place other than the wave receiving side of the diaphragm 12 or the vibration plate 12 or the horn 15 may be attached. You may attach to the place which vibrates corresponding to a vibration. When the vibration plate 12 is attached to a location other than the receiving side, it is preferable to obtain a relationship between the detection signal and the voltage V2 in advance.

  The vibration detecting means for detecting the vibration on the end side from the fixed portion of the diaphragm 12 with respect to the horn 15 only needs to output a detection signal corresponding to the vibration on the end side, and is not limited to the vibration pickups 36a and 36b. Absent. For example, a configuration in which a sound pressure signal equivalent to a vibration component is output using a microphone or the like, or a laser Doppler non-contact vibration sensor may be used. A similar configuration may also be adopted for the vibration state detection means.

  Instead of providing the current sensor 30 on the output side of the inverter circuit 28, a configuration may be adopted in which the current sensor 30 is provided on the primary side of the transformer built in the inverter circuit 28 and the output current of the inverter circuit 28 is obtained from the detection signal.

O Instead of providing the control monitor 35 independently of the power supply device 23, a display unit may be provided on the casing of the power supply device 23 and information such as a resonance frequency may be displayed on the display unit.
○ As the control monitor 35 and the display unit, the display can be selected with a touch panel, and by touching the display of the resonance frequency displayed on the panel, a screen for displaying information related to the resonance frequency can be selected. Alternatively, the excitation condition of the vibrator 13 may be selected.

  ○ No control monitor 35 is provided, and a function for communication with other devices or an input / output function for portable storage media (various discs, memory cards, etc.) is added and information such as resonance frequency and excitation are added. It is good also as a structure which delivers conditions.

○ The constant current control means and the constant voltage control means may be provided independently.
When the traveling wave is generated in the vibration plate 12, the load circuit 25 may not consume the electric energy converted from the vibration energy by the piezoelectric elements 17 a and 17 b configuring the receiving-side vibrator 14.

  The object levitation transfer device may be configured such that a standing wave is generated without generating a traveling wave on the diaphragm 12 to float the object M, and the driving force for the object M uses a force other than sound waves. For example, as shown in FIG. 6, the object levitating and conveying apparatus 40 includes a roller conveyor apparatus 41 and a sonic levitating unit 42 as a sonic levitating apparatus. In this apparatus, the object M is levitated by the action of sound waves by the sonic levitation unit 42, but the force (propulsive force) for moving (conveying) the object M is given by the roller conveyor device 41. The roller conveyor device 41 includes a plurality of rotating shafts 44 provided between the pair of side walls 43 a of the support plate 43 and rollers 45 that rotate integrally with the rotating shaft 44. The rotating shaft 44 is rotated by a motor 46 via a belt transmission mechanism. Due to the standing wave generated from the diaphragm 12, the central portion of the object M is levitated from the surface of the diaphragm 12. However, both end portions of the object M are held in contact with the stepped portion 45 a of the roller 45. Then, a thrust is applied to the object M by the rotation of the roller 45, and the object M is conveyed along the side wall 43a. In addition, as the object M, it applies to conveyance of a thin glass plate (thickness 1 mm or less), for example.

  The present invention may be applied to an object levitation device that generates a standing wave on the diaphragm 12 and holds the object M in a levitation state. In this case, the receiving-side vibrator 14 does not need the load circuit 25 for consuming electric energy converted from vibration energy by the piezoelectric elements 17a and 17b.

  ○ When the width of the object M to be transported is wide, a plurality of units of the diaphragm 12 and the vibrators 13 and 14 may be arranged in parallel, and the vibrators 13 of each unit may be connected in parallel to a common power supply device. Good. In this case, the wide object M can be transported in a stable floating state by the plurality of diaphragms 12.

  In the object levitating and conveying apparatus 11 that generates a traveling wave, both vibrators 13 and 14 coupled to one end side and the other end side of the diaphragm 12 are configured to be switchably connectable to an oscillator 22 so that the excitation side and the wave receiving side can be connected. You may comprise so that the side can be switched. In this case, the traveling direction of the traveling wave can be changed from one end side to the other end side of the diaphragm 12 or from the other end side to the one end side by switching the connection state of the oscillator 22. Therefore, when the object M is transported in the levitation state, it is easy to brake the object M that is moving in the levitation state and stop it at a predetermined position by switching the direction of the traveling wave.

The shape of the horn 15 is not limited to a flat rectangular parallelepiped shape, and may be a shape with a thin tip such as a columnar shape or a truncated cone shape.
The fixing of the diaphragm 12 to the horn 15 is not limited to the fastening with the screw 16, and an adhesive may be used, or may be fixed by brazing or welding.

The following technical idea (invention) can be understood from the embodiment.
(1) Before Symbol frequency sweep means prior to normal operation, it performs frequency sweeping, the the memory means all the resonant frequency is stored.

(2) pre-Symbol vibrating state detection means is capable of detecting a voltage sensor corresponding voltage and phase to the vibration state of the reception side.
In this specification, “the receiving side of the vibrating body” refers to the position of the vibrating body corresponding to the fixed portion connected to the vibrating body at a position away from the vibrator on the excitation side and the excitation to the fixed portion. This means the side farther from the vibrator on the side.

The schematic perspective view of the object levitation conveyance apparatus in 1st Embodiment. Schematic side view of the object levitation transfer device The block circuit diagram of the drive power supply. The schematic diagram which shows the power supply for a drive and a monitor. The schematic perspective view of the object levitation conveyance apparatus in 2nd Embodiment. The schematic perspective view of the object levitation conveyance apparatus in another embodiment.

Explanation of symbols

  M ... object, 11 ... object levitation transfer device as sonic levitation device, 12 ... diaphragm as vibration body, 13, 14 ... vibrator, 15 ... horn, 22 ... oscillator, 26 ... voltage sensor as vibration state detection means , 27... DC constant voltage generation circuit constituting constant voltage control means and constant current control means, 29... Control device constituting constant voltage control means and constant current control means and constituting frequency sweep means, 32. 35, a control monitor as a display device, 36a, 36b, a vibration pickup as vibration detecting means.

Claims (6)

A sound levitation device that excites an excitation-side vibrator connected to one end of a long vibrator and floats an object using ultrasonic radiation pressure generated by vibration of the vibrator,
Constant voltage control means for constant voltage control of an oscillator for exciting the excitation-side vibrator;
Frequency sweeping means for sweeping the output of the oscillator by constant voltage control over the entire frequency range set in advance;
Vibration state detecting means for detecting an output voltage output by a receiving-side vibrator connected to the other end of the vibrator ;
It said frequency sweep means stores the resonant frequency of at least the vibrator becomes large amplitude in the resonance frequency and the second becomes the maximum amplitude of the frequency of the output peaks of the vibration state detection means at the time of the frequency sweep by said frequency sweep means Storage means for storing the phase of the supply voltage supplied to the excitation-side vibrator and the phase of the output voltage output from the receiving-side vibrator during frequency sweeping by
Discrimination means for discriminating a vibration mode of the vibrating body based on a phase difference between the phase of the supply voltage and the phase of the output voltage stored in the storage means;
Of the resonance frequencies stored in the storage means, the resonance frequency at which the amplitude of the vibrating body is maximized is selected as a reference resonance frequency from the frequencies determined by the determining means that the vibrating body vibrates in a fringe mode. A sound levitation device comprising: selection means for performing the operation.   The sonic levitation device according to claim 1, further comprising constant current control means for performing constant current control of the oscillator, wherein the oscillator is controlled at constant current during normal operation.   The sonic levitation apparatus according to claim 2, wherein the constant current control unit and the constant voltage control unit are configured by the same circuit. The sound storage device according to claim 1 , wherein the storage unit further stores a value corresponding to an amplitude of the vibrating body at each resonance frequency . 5. The acoustic wave levitation device according to claim 1 , further comprising a display device that displays at least a resonance frequency of the vibrating body and a vibration mode of the vibrating body determined by the determining unit. The said vibration body is being fixed to the horn, The vibration detection means which detects the vibration of an edge part side from the fixed location with respect to the said horn of the said vibration body is provided. Sonic levitation device .

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