JP2002292337A - Method and device for controlling part feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling a part feeder which can correctly be vibrated by a simple structure and is free from an unnecessary vibration and attenuation. SOLUTION: A vibration element 16 vibrating at a prescribed frequency, a vibration device 14 fitted with the element 16. a vibration circuit 20 for driving the element 16, and a control part 22 which sends a driving signal to the circuit 20 for a prescribed vibration of the circuit 20 are provided. A signal detecting means which drives the element 16 temporarily at a frequency different from an ordinary driving frequency every prescribed driving frequency of the element 16 and detects a signal waveform obtained from the element 16 during the vibration period is provided in the control part 22. The control part 22 has a phase difference detecting means for detecting the phase difference between a vibration signal waveform and the driving signal waveform of the circuit 20 and a vibration controlling means for controlling the vibration of the element 16 based on the obtained phase difference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a parts feeder for supplying a vibrating bowl or the like containing various components by vibrating an electromagnet or a piezoelectric vibrator.

[0002]

2. Description of the Related Art Conventionally, for example, as a piezoelectric vibration type part feeder, as shown in FIG. 5, a bowl 2 for accommodating a part to be supplied and discharging the part while vibrating, and a predetermined resonance of the bowl 2 There is a piezoelectric vibration type part feeder including a vibration device 4 having a piezoelectric vibrator driven at a frequency and a piezoelectric drive control device 5 driving the vibration device 4. This piezoelectric vibrating parts feeder electrically detects the amplitude of the bowl 2 by an amplitude sensor 6 such as a photoelectric conversion element or a piezoelectric element, and feeds it back to a controller 5 which is a piezoelectric drive control device to drive the bowl 2 with a current or The voltage was controlled and the bowl was always driven with a constant amplitude.

Further, as disclosed in Japanese Patent Application Laid-Open Nos. 7-60187 and 10-49237,
Controls the drive signal of the piezoelectric vibrator drive circuit by performing predetermined calculations and processes based on signals obtained from current and voltage detectors connected to the drive circuit without using a special amplitude sensor. Has also been proposed.

[0004]

In the former case of the prior art, an amplitude sensor 6 for detecting the vibration of the bowl 2 is required, which complicates the structure, increases the number of parts and the circuit structure, and increases the cost. Was something. In the latter case of the above-mentioned prior art, a special amplitude sensor may not be provided. However, in order to control the vibration of the vibrating device 4 by detecting a current value or the like at the time of driving, an extra operation or high-speed calculation is required. This requires control of processing and the like, the controller 5 becomes complicated, the apparatus becomes large, and the cost increases.

Further, the applicant of the present application has proposed a device in which the driving of the piezoelectric vibrator or the electromagnet is temporarily stopped, and the driving of the piezoelectric vibrator or the electromagnet is controlled based on a signal obtained during the suspension. I have. However, in the case of using the piezoelectric vibrator of this system, an LC circuit is formed by the output transformer and the piezoelectric vibrator, and the LC resonance waveform is superimposed on the vibration signal when the vibration is temporarily stopped. Therefore, it is necessary to insert a resistor in series in order to absorb the LC resonance energy, and furthermore, some large parts feeders have a problem that an attenuation sound is generated. In the case of using an electromagnet of the above-described type, the electromagnet is not a magnet during a pause, so it is necessary to supply a DC signal to the electromagnet in order to obtain an induced electromotive force signal due to inertial vibration, which is technically and cost-effective. Is difficult to implement.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a simple structure, capable of performing accurate vibration, and a method and apparatus for controlling a parts feeder without unnecessary vibration and attenuation. The purpose is to provide.

[0007]

SUMMARY OF THE INVENTION The present invention provides a vibrating element which is a piezoelectric vibrator or an electromagnet vibrating at a predetermined frequency, a vibrating device provided with the vibrating element, and a vibrating device which is vibrated by the vibrating device. A method for controlling a parts feeder, comprising: a bowl for discharging components; a driving circuit for driving the vibrating element; and a control unit for sending a driving signal to the driving circuit and performing a predetermined driving, the method comprising: The driving of the vibrating element is temporarily performed at a frequency different from the normal driving frequency for each of the driving cycles. The different frequency is preferably a frequency that is an integral multiple or a fraction of the drive frequency of the vibrating element. During the driving period at the different frequency, the detection signal obtained by the vibrating element is subjected to frequency analysis such as Fourier transform, which is a known analyzing means, and the amplitude and phase of the vibration signal due to the bowl vibration are detected. And a method of controlling a parts feeder for controlling the vibration of the vibration element.

In the above control, the resonance frequency of the parts feeder is measured in advance. In measuring the resonance frequency, the driving element drives the vibrating element, and the driving circuit drives the driving element at predetermined intervals, at a frequency different from the normal driving frequency of the driving circuit, during this driving period. A signal obtained from the vibrating element is subjected to Fourier transform, and a power spectrum and a phase of the vibration signal of the bowl in the obtained analysis data are calculated. Then, the obtained vibration signal, the phase difference between the signal waveform and the drive signal of the drive circuit, and the resonance frequency are stored in a storage element, and the vibration device is driven at the stored resonance frequency when the vibration device is driven. Further, in the control of the vibration element, the phase difference between the obtained signal waveform and the drive signal of the drive circuit is controlled to be the stored phase difference.

According to the present invention, there is provided a vibration element which is a piezoelectric vibrator or an electromagnet which vibrates at a predetermined frequency, a vibration device provided with the vibration element, a bowl for discharging a component inside by the vibration device, A driving circuit for driving the vibrating element, and a control unit that sends a driving signal to the driving circuit and performs predetermined driving, and temporarily drives the vibrating element for each predetermined driving cycle of the vibrating element. The control unit is provided with a signal detecting means for detecting a signal waveform obtained from the vibrating element during the vibration period while performing the driving at a frequency different from the normal driving frequency. Further, the control unit includes: a phase difference detection unit configured to detect a phase difference between a vibration signal waveform of the signal waveform obtained by the signal detection unit and a drive signal waveform of the drive circuit; and the phase difference detection unit. A vibration control means for controlling vibration of the vibration element based on the obtained phase difference.

In the present invention, the signal indicates a voltage and a current. When the signal is a voltage, the terms including the signal include a voltage waveform, a driving voltage, a voltage detecting means, and a driving voltage waveform. In the case of a current, a current waveform, a drive current, a current detection unit, and a drive current waveform are used.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The parts feeder according to the present embodiment relates to a piezoelectric vibrating parts feeder 10, as shown in FIG. 1, a bowl 12 for accommodating and vibrating and discharging various parts, and a piezoelectric vibrating device 14 for vibrating the bowl 12. Is provided. The piezoelectric vibrating device 14 includes the bowl 12
And a piezoelectric vibrator 16 as a vibration element for vibrating the elastic support.

Next, the control device 40 for driving the piezoelectric vibrator 16 will be described below. The piezoelectric vibrator 16 is connected to a drive circuit 20 composed of a power amplifier or the like, and the drive circuit 20 is connected to an output terminal of a control unit 22 composed of a microcomputer or the like that sends a drive signal of the piezoelectric vibrator 16. Further, the piezoelectric vibrator 16 is connected to a voltage detection circuit 24 for detecting a voltage generated at the electrode, and an output of the voltage detection circuit 24 is connected to an A / D conversion input terminal of the control unit 22.

An amplitude setting circuit 26 for adjusting the amplitude of the piezoelectric vibrator 16 via a drive circuit 20 is provided in the control unit 22.
Is connected. In addition, a mode setting circuit 28 that switches the drive mode of the parts feeder 10 between the adjustment mode and the operation mode is connected to the control unit 22. Further, the nonvolatile memory 30 is a storage element that stores data such as a predetermined voltage value, phase difference, and frequency, and inputs and outputs the data to and from the control unit 22.

As shown in FIGS. 2 to 4, the driving method and the control method of the piezoelectric vibrating parts feeder 10 of this embodiment are as follows. First, power is turned on and the driving mode of the piezoelectric vibrating parts feeder 10 is set to the mode. The selection is made by the setting circuit 28. Normally, when the piezoelectric vibrating parts feeder 10 is shipped, the resonance frequency of the piezoelectric vibrating parts feeder 10 is measured and stored. Further, when the natural frequency of the vibration system changes when the bowl 12 is replaced or other parts are replaced, the resonance frequency also changes. Remember. As shown in FIG. 3, the piezoelectric vibration device 14 has the maximum amplitude at the resonance frequency of the device including the bowl 12, so that the driving circuit 20 sweeps the frequency without changing the driving voltage, and the amplitude becomes maximum. The frequency is detected and set as the resonance frequency.

Next, the piezoelectric vibrator 16 is driven by the drive circuit 20 at the set amplitude and its resonance frequency. Then, when the operation mode is set, the driving of the drive circuit 20 is performed at a predetermined cycle as shown in FIG.
Period only driven at twice the frequency f ₂ of the normal drive frequency f, and detects the voltage obtained by the piezoelectric effect of the piezoelectric vibrator 16 during the t period by the voltage detection circuit 24, the control unit the voltage signal 22 to the A / D conversion input terminal. The control unit 22 converts the input voltage signal into a digital signal, performs a Fourier transform on the digitized vibration signal,
Perform frequency analysis. In this embodiment, FIG.
As shown in (C), the primary waveform subjected to the Fourier transform is the vibration signal waveform of the piezoelectric vibrating device 14 and the like, and the secondary waveform is the drive signal waveform output from the drive circuit 20. And
The obtained amplitude of the vibration signal waveform, the phase difference with the drive signal, and the resonance frequency are stored in the nonvolatile memory 30. The above-described operation of measuring the resonance frequency and the like is automatically performed by a predetermined program. Further, the amplitude of the piezoelectric vibration device 14 at the time of driving at the resonance frequency is set by the amplitude setting circuit 26.

Next, when the operation is actually performed by supplying parts, the operation mode is switched to the operation mode by the mode setting circuit 28.
The driving circuit 20 drives the piezoelectric vibrator 16 at the resonance frequency and the amplitude stored in the nonvolatile memory 30. At this time, a predetermined period of driving of the drive circuit 20, for example, temporarily at every 50 cycles, a predetermined t period, as shown in FIG. 4 (A), driven at twice the frequency f ₂ of the normal drive frequency f I do. At this time, a voltage obtained by the piezoelectric effect from the piezoelectric vibrator 16 is detected by the voltage detection circuit 24 and the control unit 22
Is output to The control unit 22 performs A / D conversion on the voltage waveform obtained by the voltage detection circuit 24 during the period t, further performs Fourier transform on the digitized vibration signal, and obtains the vibration signal of the bowl 12 (FIG. 4 (B))
And the phase difference between the excitation force and the waveform of the drive signal for driving the drive circuit 20 is calculated. The controller 22 controls the piezoelectric vibrator so that the phase difference between the vibration signal waveform obtained from the piezoelectric vibrator 16 and the drive signal waveform of the drive voltage of the drive circuit 20 becomes the above-described phase difference stored in the adjustment mode. The vibration frequency of the child 16 is controlled. This control is continued at predetermined intervals during the operation of the piezoelectric vibration type part feeder 10.

According to the method and the apparatus for controlling the piezoelectric vibration type part feeder of this embodiment, the mechanical vibration of the piezoelectric vibrator 16 can be controlled without using a special sensor for detecting the amplitude.
The signal detected during the period in which the drive frequency is temporarily changed can be accurately detected by the piezoelectric vibrator 16 itself.
2 sends a detection signal. Then, a vibration signal can be easily and accurately obtained by Fourier transform, and accurate drive control can be performed by accurate amplitude and phase detection. Moreover, since the piezoelectric vibrator 16 itself is used as a sensor, the configuration is simple and the detection signal is extremely accurate. Also,
Even if the driving frequency of the piezoelectric vibrator 16 is temporarily changed, the bowl 12 and the vibrating device 14 vibrate by inertia, so that there is no problem in driving the piezoelectric vibrating device 14.

Further, it is possible to switch between an adjustment mode and an operation mode.
Can be adjusted as necessary, and can always be driven in an appropriate state.

When the parts feeder 10 is a self-excited type, accurate vibration can be obtained by controlling the frequency so that the phase of the voltage obtained from the piezoelectric vibrator 16 becomes the same as that at the time of measuring the resonance frequency. Become. In the case of a separately excited type,
The user sets a predetermined frequency. In this case as well, accurate resonance frequency control can be performed by detecting the phase of the vibration voltage and the drive voltage of the piezoelectric vibrator.

The present invention is not limited to the above-described embodiment, and may be an electromagnetic vibrating parts feeder using an electromagnet as a vibrating element in addition to a vibrating parts feeder using a piezoelectric element. Further, the frequency to be temporarily changed may be another integer multiple or a fraction of an integer other than the double frequency. In particular, an even-numbered frequency or an even-numbered frequency is preferable. Furthermore, it is sufficient that the vibration signal waveform can be obtained by Fourier transformation, and the frequency to be changed is not limited. Preferably, when the frequency of the normal drive signal is high, the frequency of the drive signal to be temporarily changed to a lower frequency than the normal drive signal is set, and when the normal drive signal is relatively low, the signal frequency to be changed is set. Should be higher.

The driving method of the parts feeder 10 is as follows.
It can be set as appropriate. Furthermore, in addition to detecting the voltage obtained by the piezoelectric effect of the piezoelectric vibrator 16 and the induced electromotive force of the electromagnet, it also detects the current flowing through the piezoelectric vibrator and the electromagnet,
It is also possible to perform a Fourier transform and obtain a vibration frequency and control it in the same manner as described above. In addition, the present invention can be used not only for a part feeder having a bowl, but also for a general part supply device using a piezoelectric vibrator or an electromagnet.

[0022]

The method and apparatus for controlling a parts feeder according to the present invention enable accurate vibration detection using the vibration element itself as a sensor without using a special amplitude sensor for detecting the amplitude of the vibration element. In addition, since the vibrating element is temporarily driven at a different frequency and the actual vibration signal is obtained by analyzing the frequency of the detection signal during the driving, and the driving control is performed, the control content can be made very simple. Also, since the resonance frequency of the parts feeder is measured and stored once, and the operation is performed based on the stored resonance frequency and other signals and data of the phase difference, the individual parts feeder is operated under the optimum driving condition. Can be driven. Also, when the configuration of the parts feeder changes, the resonance frequency can be measured again, and the drive can always be performed under appropriate conditions.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a piezoelectric vibration type parts feeder according to an embodiment of the present invention.

FIG. 2 is a flowchart showing control contents of a piezoelectric vibration type part feeder of the embodiment.

FIG. 3 is a graph showing a relationship between a resonance frequency and an amplitude of the piezoelectric vibration type part feeder of the embodiment.

FIG. 4 is a graph (A) showing a driving waveform of the piezoelectric vibration type part feeder of this embodiment, and a vibration signal (B) and a driving signal (C) obtained by Fourier transform.

FIG. 5 is a schematic diagram showing a conventional method of controlling a parts feeder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Piezoelectric vibration type part feeder 12 Bowl 14 Piezoelectric vibration device 16 Piezoelectric vibrator 20 Drive circuit 22 Control part 24 Voltage detection circuit 26 Amplitude setting circuit 28 Mode setting circuit 30 Storage element 40 Control device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F037 AA06 BA01 CA14 CC03 5D107 AA06 AA16 BB04 BB05 BB06 CC01 CD03

Claims (4)

[Claims] A vibrating element (1) vibrating at a predetermined frequency.
6), a vibrating device (14) provided with the vibrating element (16), a driving circuit (20) for driving the vibrating element (16), and a driving signal sent to the driving circuit (20) to transmit a predetermined signal. In the method for controlling a parts feeder (10) having a control unit (22) for performing driving, the vibration element (1)
6) A method of controlling a parts feeder, wherein the driving of the vibrating element (16) is temporarily performed at a frequency different from a normal driving frequency for each predetermined driving cycle. 2. The parts feeder according to claim 1, wherein the frequency different from the normal driving frequency is a frequency that is an integral multiple or a fraction of the normal driving frequency of the vibrating element. Control method. 3. A frequency analysis of a detection signal obtained by the vibrating element (16) during a driving period at a frequency different from the normal driving frequency, and a bowl (12) provided in the vibrating device (14) is provided. 3. The method of controlling a parts feeder according to claim 1, wherein an amplitude and a phase of a vibration signal caused by the vibration are detected to control the vibration of the vibration element. 4. A vibrating element (1) vibrating at a predetermined frequency.
6), a vibrating device (14) provided with the vibrating element (16), a bowl (12) for discharging components inside by the vibrating device (14), and a drive for driving the vibrating element (16) A circuit (20); and a control unit (22) for sending a drive signal to the drive circuit (20) and performing a predetermined drive. The control unit (22) is provided for every predetermined drive cycle of the vibration element (16). The driving of (16) is temporarily performed at a frequency different from the normal driving frequency, and signal detecting means for detecting a signal waveform obtained from the vibrating element (16) during the vibration period is provided to the control unit (22). The control section (22) is further provided with a phase difference detecting means for detecting a phase difference between a vibration signal waveform of the signal waveform obtained by the signal detecting means and a drive signal waveform of the drive circuit (20). When,
A vibration control means for controlling the vibration of the vibration element (16) based on the phase difference obtained by the phase difference detection means.