KR20020077260A - Parts feeder and method of controlling the same - Google Patents

Abstract

PURPOSE: 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. CONSTITUTION: 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

PARTS FEEDER AND METHOD OF CONTROLLING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component feeder and a control method thereof for vibrating and supplying a bowl or the like in which various components are accommodated by vibration of an electromagnet or piezoelectric vibrator.

In a conventional production line, a vibrating parts feeder has been used to supply parts.

5 shows a piezoelectric vibrating parts feeder as an embodiment of the vibrating parts feeder. Such a piezoelectric vibrating parts feeder includes a bowl 2 as a part discharge part for accommodating and supplying a part to be supplied and discharging the part, and a vibrator 4 having a piezoelectric vibrator for driving the bowl 2 at a predetermined frequency. And a controller 5 for controlling the operation of the vibrator 4.

In such a vibrating component feeder, in order to properly control the vibration state of the bowl 2, an amplitude sensor 6 such as a photoelectric conversion element or a piezoelectric element is installed in the bowl 2 to electrically detect the amplitude of the bowl 2. The detection signal is fed back to the controller 5 so that the bowl 2 is always driven at a constant amplitude by adjusting the current or voltage for driving the bowl 2.

In addition, a current detector or a voltage detector is provided in a drive control circuit such as the controller 5, and predetermined vibration or operation is performed on the detection signals therefrom to determine the vibration state of the bowl 2, and drive from the result. By controlling the apparatus 4, the vibration state of the bowl 2 is appropriately controlled (Japanese Patent Laid-Open Nos. 7-60187 and 10-49237). In such a configuration, it is not necessary to install a special amplitude sensor in the bowl 2.

However, the above-described method using the amplitude sensor requires an amplitude sensor 6 for detecting the vibration of the bowl 2, and the configuration is complicated, and the number of parts and the circuit configuration increase, resulting in a high cost. .

In addition, although the amplitude sensor of the bowl 2 does not need to be provided in the above-described method of signal processing of the drive control circuit, a high speed arithmetic process or the like is performed to control the vibration of the vibration device 4 by detecting a drive control signal or the like. This is necessary and the controller 5 becomes complicated and expensive.

In response to this problem, the present applicant temporarily stops driving to the bowl 2 (stops driving from the driving device 4), and while the bowl 2 continues to vibrate by inertia, the bowl 2 Of a piezoelectric vibrator for driving, electromagnet or the like (typically a signal generated at a terminal to which a driving electric signal is input), and performs drive control of the drive device 4 based on this signal. The method is proposed.

However, in such a pause mode, especially when a piezoelectric vibrator is used, an LC circuit is formed by the output transformer of the driving device 4 and the piezoelectric vibrator. When the vibration is stopped, the LC resonant waveform rises on the drive signal. The precision may fall. In order to solve such a resonance waveform, it is necessary to change a resistor for absorbing LC resonance energy in series in the LC circuit. In addition, there is a problem that attenuation sound occurs in some large parts supply.

In the case where the electromagnet is used as the temporary stop method, the electromagnet is not a magnet during stop, and therefore, in order to obtain a signal of induced electromotive force by inertial vibration, it is necessary to flow a DC signal through the electromagnet. This becomes difficult to implement.

It is an object of the present invention to provide a component feeder and a control method thereof, the structure of which is simple and can carry out accurate vibration, and there is no unnecessary vibration or attenuation.

The component feeder of the present invention is a vibrating element 16 for vibrating the part ejector 12, a driving circuit 20 for driving the vibrating element 16, and driving of a predetermined driving frequency to the drive circuit 20 In the component feeder 10 having a control unit 22 which sends a signal to vibrate the vibrating element 16 at the driving frequency, the control unit 22 typically sets the driving frequency to a predetermined normal frequency. At the same time, the driving frequency is changed to a temporary frequency different from the normal frequency at every predetermined operation period.

The control method of the component feeder of the present invention includes a vibrating element 16 for vibrating the part ejector 12, a driving circuit 20 for driving the vibrating element 16, and a predetermined drive to the driving circuit 20. In the control method of the component feeder 10 having a control unit 22 which sends a driving signal of a frequency to vibrate the vibrating element 16 at the driving frequency, the driving frequency is generally set to a predetermined normal frequency. The driving frequency is changed to a pause frequency different from the normal frequency at every predetermined operation period.

In the present invention as described above, the drive frequency is usually set to a predetermined normal frequency, the component supply operation from the component ejector is executed, and the drive frequency is changed to a temporary frequency different from the normal frequency at every predetermined operation period. In this period, the operation control of the component discharge part is adjusted. That is, although the driving signal is stopped in the conventional pause method described above, in the present invention, driving signals of different frequencies are output. As a result, the vibrating element is driven inversely by the component discharging portion which continues the vibration by inertia, so that the signal corresponding to the vibration state of the component discharging portion is superimposed on the signal of the temporary frequency applied to the vibrating element. Therefore, each signal can be analyzed by, for example, frequency analysis of the signal for the vibrating element in this state, and the signal by the component discharge unit which continues the vibration by inertia, and the signal of the temporary frequency applied. Can be identified, and the drive control can be adjusted based on the signal from the component ejection unit.

In the component feeder of the present invention or a control method thereof, a signal output from the vibrating element 16 that continues to vibrate by inertia during the driving period at the temporary frequency is detected, and the detection signal and the control unit 22 are detected. It is preferable to compare the drive signal output from the control unit and to control the vibration of the vibration element 16 based on the comparison result.

In this comparison, it is preferable to obtain a phase difference between the waveform of the detection signal and the waveform of the drive signal, and to control the vibration of the vibration element 16 so that the phase difference becomes a predetermined value.

For example, although the drive signal cut into the temporary frequency is an integer multiple of the normal frequency, and the signal and the phase of the normal frequency are provided, the vibration state can be adjusted by the phase adjustment of the output signal from the vibration element.

In a specific configuration, the control section 22 includes a signal detecting means 31 for detecting a signal output from the vibrating element 16 that continues to vibrate by inertia, a vibration signal waveform obtained by the signal detecting means, and the driving circuit. Phase difference detecting means 32 for detecting a phase difference with the drive signal waveform from 20, and vibration control means 33 for controlling vibration of the vibrating element 16 based on the phase difference obtained by the phase difference detecting means. It may be provided with a.

Preferably, the temporary frequency is an integer multiple of the reference frequency or a frequency equal to one integer.

At such a temporary frequency, a phase difference can be provided with respect to a signal of a normal frequency, and amplitude and phase adjustment is performed.

As a normal frequency, it is preferable that it is the frequency of the resonant frequency of the vibration part containing the said component discharge part 12 and the vibration element 16, or its integer multiple.

With such a normal frequency, the vibration driving of the parts discharge part can be executed with good efficiency, and the vibration caused by the inertia of the parts discharge part lasts for a long time when it is switched to the temporary frequency, so that the control process can be precisely and surely secured. Can be.

The adjustment of the component feeder according to the present invention specifically performs the following operation. In advance, measure the resonant frequency of the component supplier to be adjusted. When the resonant frequency is measured, the vibration element is driven by the driving circuit, and the driving by the driving circuit is driven at a frequency different from the normal driving frequency by the driving circuit every predetermined period, and from the vibration element during this driving period. The obtained signal is Fourier transformed to calculate a phase with the power spectrum of the vibration signal of the bowl in the obtained analysis data. The vibration signal obtained, the phase difference between the signal waveform and the drive signal of the drive circuit, and the resonance frequency are stored in the storage element, and are driven as the stored resonance frequency when the vibration device is driven. 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.

In the present invention, the signal indicates a voltage and a current, and when the signal is a voltage, the term including the signal is a voltage waveform, a driving voltage, a voltage detection circuit, and a driving voltage waveform; When the signal is a current, it becomes a current waveform, drive current, current detection means, and drive current waveform.

Other objects, features and advantages of the present invention will be more clearly understood by the following detailed description with reference to the accompanying drawings.

1 is a schematic block diagram of a piezoelectric vibrating component feeder according to an embodiment of the present invention.

Fig. 2 is a flowchart showing the control contents for the embodiment.

Fig. 3 is a graph showing the relationship between the resonant frequency and the amplitude of the component feeder for the above embodiment.

Fig. 4A is a graph showing the drive waveform of the component feeder for the above embodiment.

4B is a graph showing a vibration signal obtained by Fourier transform.

4C is a graph showing a drive signal.

5 is a schematic diagram showing a control method of a conventional component feeder.

[Description of Symbols for Main Parts of Drawing]

10: piezoelectric vibratory component feeder 10: bowl

14 piezoelectric vibrator 16 piezoelectric vibrator

20: drive circuit 22: control unit

24: voltage detection circuit 26: amplitude setting circuit

28: mode setting circuit 30: memory element

40: control unit.

The parts feeder of the present invention relates to a piezoelectric vibrating parts feeder (10), as shown in Figure 1, receiving a variety of parts to vibrate and discharge, and a piezoelectric vibrator for vibrating the bowl (12) (14) is provided. The piezoelectric vibrator 14 includes an elastic support (not shown) for supporting the bowl 12 and a piezoelectric vibrator 16 as a vibrating element for vibrating the bowl 12 via the elastic support. A control device 40 is provided to drive the piezoelectric vibrator 16.

The control device 40 includes a driving circuit 20 made of a power amplifier or the like in contact with the piezoelectric vibrator 16. The drive circuit 20 is connected to the output terminal of the control unit 22 made of a microcomputer or the like for transmitting the drive signal of the piezoelectric vibrator 16. The piezoelectric vibrator 16 is connected to a voltage detection circuit 24 for the voltage generated at its electrode, and the output of the voltage detection circuit 24 is connected to the A / D conversion input terminal of the control unit 22.

The control unit 22 is connected to an amplitude setting circuit 26 for adjusting the amplitude of the piezoelectric vibrator 16 via the driving circuit 20. The control unit 22 is connected to a switching mode setting circuit 28 for switching the driving mode of the component supplier 10 to the adjustment mode. A nonvolatile memory 30, which is a storage element for storing data such as a predetermined voltage value, phase difference, frequency, and the like and outputting the data between the control unit 22, is provided.

The control unit 22 includes signal detecting means 31 for detecting a voltage signal from the voltage detecting circuit 24, a vibration signal waveform obtained by the signal detecting means 31, and a driving signal waveform from the driving circuit 20. Phase difference detecting means 32 for detecting a phase difference between the first and second phase difference means, and vibration control means 33 for controlling the vibration of the vibrating element 16 based on the phase difference obtained by the phase difference detecting means 32. Each of these means constitutes a control unit 22 as a microcomputer system, and can be realized as a software function by a program executed in such a system. In addition, you may carry out by a hardware circuit.

2 to 4 show a driving method and a control method of the piezoelectric vibrating component feeder 10 in this embodiment.

When the operation of the component supplier 10 is executed, first, the power supply of the component supplier 10 is inputted, and the mode setting circuit 28 selects the driving mode of the component supplier 10.

Normally, the resonant frequency of the piezoelectric vibrating parts supplier 10 is measured and stored in the nonvolatile memory 30 at the time of shipment of the piezoelectric vibrating parts supplier 10. On the other hand, when the bowl 12 is replaced, or when other parts are replaced and the natural frequency of the vibration system is changed, the resonance frequency also changes, so that the resonance frequency is measured and stored in the nonvolatile memory 30. . When performing such a process, the adjustment mode is used.

In the adjustment mode, since the amplitude of the piezoelectric vibrator 14 is maximized at the resonant frequency of the device including the bowl 12 as shown in FIG. 3, the driving circuit 20 does not change the driving voltage. The frequency is sweeped and the frequency at which the amplitude is maximum is detected to be the resonance frequency (S1 in Fig. 2).

Subsequently, the piezoelectric vibrator 16 is driven by the drive circuit 20 at the set amplitude and its resonant frequency in the same manner as in the operating state (S2 in Fig. 2).

Here, if the component supplier 10 is switched from the adjustment mode to the operation mode, the component supplier 10 performs a predetermined adjustment process and proceeds to the operation mode.

The component supplier 10 drives the driving circuit 20 at predetermined frequencies for a predetermined period of time, as shown in FIG. 4A, at a frequency f2 twice the normal driving frequency f. During the t period, the voltage obtained by the piezoelectric effect of the piezoelectric vibrator 16 is detected by the voltage detecting circuit 24, and the voltage signal is input to the A / D conversion input terminal of the control unit 22. The control unit 22 converts the input voltage signal into a digital signal, and Fourier transforms the digitalized vibration signal to perform frequency analysis. In this embodiment, as shown in Figs. 4B and 4C, the Fourier transformed primary waveform is a vibration signal waveform of the piezoelectric vibrator 14 or the like, and the secondary waveform is a drive signal waveform output from the driving circuit 20. do. Then, the amplitude of the obtained vibration signal waveform, the phase difference with the drive signal, and the resonance frequency are calculated (process S3 in FIG. 2) and stored in the nonvolatile memory 30 (process S4 in FIG. 2).

The above measurement operation of the resonance frequency (S1 in Fig. 2) and phase measurement and amplitude measurement operations (S2-S4 in Fig. 2) are automatically executed by a predetermined program. The amplitude of the piezoelectric vibrator 14 during driving at the resonance frequency is set by the amplitude setting circuit 26.

After such adjustment, the mode setting circuit 28 is switched to the operation mode in the case of actually operating by supplying parts.

In the operation mode, the piezoelectric vibrator 16 is driven by the drive circuit 20 at the resonance frequency and amplitude stored in the nonvolatile memory 30 (S5 in Fig. 2).

At this time, the driving of the driving circuit 20 is driven at a frequency f2 twice the normal driving frequency f only for a predetermined t period as shown in FIG. 4A for a predetermined period, for example, temporarily. do. At this time, the voltage obtained by the piezoelectric effect from the piezoelectric vibrator 16 is detected by the voltage detection circuit 24 and output to the control unit 22. The control unit 22 performs A / D conversion of the voltage waveform obtained by the voltage detection circuit 24 for the period t, Fourier transforms the digitized vibration signal, and obtains the vibration signal of the bowl 12 (FIG. 4B). And the phase difference between the waveform of the drive signal for driving the drive circuit 20 which is the excitation force (S6 in Fig. 2).

Then, the control unit 22 controls the piezoelectric vibrator 16 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 phase difference stored in the adjustment mode. Control the oscillation frequency (S7 in FIG. 2).

This control is continued at predetermined intervals as long as the piezoelectric vibrating component feeder 10 is in the operation mode during operation. On the other hand, when the component supplier 10 is switched to the adjustment mode, the above-described processes (S1 to S4) are executed.

According to the method and apparatus for controlling a piezoelectric vibrating component feeder according to the present embodiment, the piezoelectric vibrator detects the mechanical vibration of the piezoelectric vibrator 16 during a temporary change period of the driving frequency without using a special sensor for detecting the amplitude. (16) It can detect correctly, and can transmit a detection signal to the control part 22. The vibration signal can be obtained easily and accurately by the Fourier transform, and accurate driving control can be obtained by accurate amplitude and phase detection. However, since the piezoelectric vibrator 16 itself is used as a sensor, the configuration is simple and the detection signal is also very accurate. Further, even if the driving frequency of the piezoelectric vibrator 16 is temporarily changed, since the bowl 12 and the vibrator 14 vibrate inertia, there is no problem in driving the piezoelectric vibrator 14 at all.

In addition, it is possible to switch between the adjustment mode and the operation mode, and by the adjustment mode, the optimum resonant frequency of the component feeder 10 can be adjusted as necessary, and it can always be driven in an appropriate state.

In addition, when the component supplier 10 is a self-vibrating type, if the frequency is controlled so that the phase of the voltage obtained from the piezoelectric vibrator 16 is the same as the phase difference when the resonance frequency is measured, accurate vibration is possible. In the case of the self-vibration type, the user sets a predetermined frequency, but in this case, accurate resonance frequency control is possible by detecting the vibration voltage and the driving voltage of the piezoelectric vibrator.

In addition, the present invention is not limited to the above embodiment, and in addition to the vibrating component feeder using a piezoelectric element, the present invention may be used in an electronic vibrating component feeder using an electromagnet for the vibrating element.

The normal frequency is preferably the resonant frequency (intrinsic frequency) of the vibration part including the component discharge part or an integer multiple thereof, since the continuation of vibration is easily obtained even between the effective vibration impartation and the temporary vibration impartation stop, but the vibration between the vibration impulse stops described above. If this is obtained, other frequencies may be used.

The temporary frequency may be an integer multiple of one other than the frequency twice the normal frequency, or a frequency equal to one integer. In particular, an even frequency or an even frequency is preferable. In this manner, the phase comparison can be easily performed in addition to the effect that the vibration continuity of the vibration part including the component discharge part is easy to be obtained even between the stops of the vibration impartation by the normal frequency.

In addition, it is sufficient if the vibration signal waveform can be obtained by the Fourier transform, and the frequency to be deformed is not a problem. Preferably, when the normal frequency is high, the temporary frequency may be set to a frequency lower than the normal frequency, and when the normal frequency is relatively low, the temporary frequency may be increased.

In addition, the driving method of the component supplier 10 can be set suitably. In addition to detecting the voltage obtained by the piezoelectric effect of the piezoelectric vibrator 16 or the induced electromotive force of the electromagnet, the current flowing through the piezoelectric vibrator or the electromagnet can be detected and Fourier transformed to obtain a vibration frequency and controlled in the same manner as described above. In addition, the use can be generally used in parts supply apparatus using a piezoelectric vibrator or an electromagnet, in addition to the parts supply having a bowl.

As described above, the present invention enables 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. Moreover, since the vibration element is temporarily driven at a different frequency, the detection signal therebetween is frequency-analyzed to obtain the actual vibration signal, and the drive control can be made with very simple control contents. In addition, since the resonant frequency of the component feeder is measured and stored once, and operated based on the stored resonant frequency and other signals or data of the phase difference, each component feeder can be driven under optimum driving conditions. In addition, even when the component supply configuration changes, the resonance frequency may be measured and corrected again, and may be driven under very suitable conditions.

Claims (10)

A vibration device 16 for vibrating the component ejector 12, a drive circuit 20 for driving the vibration device 16, and a drive signal of a predetermined drive frequency to the drive circuit 20 to send the vibration device. A component feeder (10) having a control unit (22) for vibrating (16) at the drive frequency, The control part (22) generally makes the drive frequency a predetermined normal frequency and at the same time changes the drive frequency to a temporary frequency different from the normal frequency every predetermined operation period. 2. The control unit 22 according to claim 1, wherein the control unit 22 detects a signal output from the vibrating element 16 that continues to vibrate by inertia during the driving period at the temporary frequency, and the detection signal and the control unit 22 And a drive signal output from the control unit, and suppressing the vibration of the vibration element based on the result of the comparison. 3. The control unit (22) according to claim 2, wherein the controller (22) includes: signal detecting means (31) for detecting a signal output from the vibrating element (16) which continues to vibrate by inertia, and a vibration signal waveform obtained from the signal detecting means; Vibration control for controlling the vibration of the vibration element 16 on the basis of the phase difference detection means 32 for detecting the phase difference with the drive signal waveform from the drive circuit 20 and the phase difference obtained by the phase difference detection means. A component feeder comprising means (33). The component feeder of claim 1, wherein the temporary frequency is an integer multiple of a reference frequency or one frequency of an integer. The component feeder according to claim 1, wherein the normal frequency is a frequency of a resonant frequency of an oscillation part including a component discharge part (12) and a vibration element (16) or an integer multiple of the frequency thereof. A vibration device 16 for vibrating the component ejector 12, a drive circuit 20 for driving the vibration device 16, and a drive signal of a predetermined drive frequency to the drive circuit 20 to send the vibration device. A control method of a component feeder (10) having a control unit (22) for vibrating (16) at the drive frequency, Normally, the drive frequency is set to a predetermined normal frequency and at the same time the operation frequency of the component feeder control method characterized in that to change the drive frequency to a different stop frequency than the normal frequency. 7. A signal according to claim 6, wherein a signal output from the vibration element (16) which continues to vibrate by inertia during the driving period at the temporary frequency is detected, and the detection signal and the drive signal output from the control unit (22) are detected. And controlling the vibration of the vibrating element (16) based on the comparison result. 8. The method as claimed in claim 7, wherein the phase difference between the waveform of the detection signal and the waveform of the drive signal is obtained and the vibration of the vibration element 16 is controlled so that the phase difference becomes a predetermined value. . 7. The component feeder control method according to claim 6, wherein the temporary frequency is an integer multiple of the reference frequency or one frequency. 7. The component feeder control method according to claim 6, wherein the normal frequency is a resonant frequency of an oscillating portion including a component ejecting portion (12) and a vibrating element (16) or an integer multiple of the frequency thereof.