JPH11116029A - Method and device for driving and controlling electromagnetic vibration feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a desired resonance tracking control during driving with performing soft start, by gradually increasing voltage after starting of driving up to a given level and by setting a driving frequency to a constant frequency close to a resonance frequency. SOLUTION: A constant amplitude control circuit 22 is connected to a variable frequency power supply 10, with which an amplitude instructing circuit 21 for providing a given amplitude instruction is connected. The constant amplitude control circuit 22 is equipped with a circuit for linearly changing a voltage until a given time after starting of driving. The variable frequency power supply 10, after closing of a switch S, supplies a resonance frequency which is supplied from a memory circuit 15 and stored after previous finishing of driving, and during the closing of the switch S, supplies this frequency to the amplifier 12 side through the constant amplitude frequency control circuit 22. The variable frequency power supply 10 performs a constant amplitude action to the constant amplitude frequency control circuit 22 at a finishing time of a soft start, receives outputs from a phase detecting circuit 11, and performs original resonance tracking control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control method and apparatus for an electromagnetic vibration feeder.

[0002]

2. Description of the Related Art In an apparatus of this kind, a rising characteristic at the start of driving of an electromagnetic vibration feeder, for example, a vibration parts feeder is performed as shown in FIG. That is, the voltage applied to the coil to substantially linearly increase until time t _0. The voltage after t ₀ is constant as a voltage for a predetermined amplitude. As a result, the parts in the bowl of the vibrating parts feeder, for example, the chip-shaped parts, at the start of driving, are positioned at the part alignment means, for example, the parts located in the vicinity of the wiper for making the plate-shaped parts into a single layer. A single layer is supplied to the side. However, the frequency of the bowl of the vibrating parts feeder in the resonance tracking control changes as shown in FIG. 8 after the start of driving. That is, the frequency initially rises from the frequency at the start of the driving, then decreases, and after time t _0, it shows the course as shown in the figure. This is due to the resonance point change as shown in FIG. .

FIG. 10 shows frequency-amplitude (vibration displacement) characteristics when the voltage of the coil of the vibration parts feeder is changed to 20 volts, 30 volts, 40 volts, 50 volts, 60 volts and 70 volts. However, for the same vibrating parts feeder, the voltage is increased, that is, the amplitude is increased for a certain frequency. As the amplitude increases, the resonance frequency decreases. For example, as shown in FIG. 10, when the coil voltage is 70 volts, the resonance point is about 54.2.
It is about 55.8 Hertz when the coil voltage is 20 volts compared to Hertz. Such a change in the resonance point is caused by the fact that, as is known, the vibrating parts feeder is composed of a bowl and a base connected by inclined leaf springs arranged at equal angular intervals. Used as a spring. If the torsional amplitude becomes large,
The effective length provided for vibration between the bolts fixing the upper and lower ends increases. Thereby, the spring constant of the leaf spring decreases. That is. The resonance frequency decreases. This is considered to be one factor. FIG. 10 shows the transition of the resonance frequency when the coil voltage is changed from 20 volts to 70 volts as described above. This is an experimental example.
As shown in FIG. 8, when the coil voltage is gradually changed until time t ₀ , the resonance frequency decreases as the amplitude increases at the time of resonance. The temporal change of the driving frequency as shown is seen. In the vicinity of the resonance point, the amplitude fluctuates greatly even if the frequency slightly changes. Although this is an unstable area, the vibration displacement of the bowl changes as shown in FIG. That is, at first, the change in the displacement of the vibration approximated to the rise of the coil voltage in FIG. 7 can be obtained, but due to the phenomenon shown in FIG. 8, the vibration displacement rapidly increases until time t _0. There is a time range, and a so-called hunting phenomenon that the temperature rapidly decreases and increases after the time t ₀ is exhibited, and the control becomes unstable.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a drive control method of an electromagnetic vibration feeder capable of performing desired resonance tracking control during driving while performing an original soft start, and a method thereof. It is an object to provide a device.

[0005]

The above object is achieved by connecting a movable part and a base with a spring, attaching an electromagnet to the movable part or the base, and applying a voltage applied to a coil of the electromagnet and the movable The phase difference from the vibration displacement of the part is detected, and the phase difference is 18
The frequency of the voltage applied to the coil was increased or decreased so as to be 0 degrees, so that resonance oscillation was performed. At the start of driving, the voltage was gradually increased to a predetermined height, and was thereafter kept constant. In the drive control method for an electromagnetic vibration feeder, the drive frequency is set to a constant frequency close to a resonance frequency until the voltage after the start of driving reaches the predetermined height. Is done. Or, connect the movable part and the base with a spring,
An electromagnet is attached to the movable part or the base, and a phase difference between a voltage applied to a coil of the electromagnet and a vibration displacement of the movable part is detected by a phase difference detector, and the phase difference becomes 180 degrees. As described above, the frequency of the voltage of the variable frequency power supply to be applied to the coil is increased / decreased so as to cause resonance oscillation, and the voltage adjusting means for receiving the voltage of the variable frequency power supply causes the voltage to have a predetermined height at the start of driving. In the drive control device of the electromagnetic vibration feeder, which is gradually increased to a constant frequency thereafter, the drive frequency is a constant frequency close to the resonance frequency until the voltage after the start of driving reaches the predetermined height. The problem is solved by a drive control device for an electromagnetic vibration feeder characterized by the above.

With the above configuration, at the start of driving, the coil voltage is changed at a predetermined driving frequency as shown in FIG. During this time, since the driving frequency is constant, a desired change in vibration displacement is obtained, and a single-layer supply of components can be performed smoothly, for example, without applying a shocking transfer force to components in the bowl. . After the set time of the soft start, the resonance tracking control is performed in the same manner as in the related art, and the transfer is always performed at the resonance frequency following the fluctuation of the resonance frequency over time, so that this characteristic can be exhibited.

[0007]

1 and 2 show block diagrams of a resonance tracking control circuit according to an embodiment of the present invention. Hereinafter, embodiments of the present invention will be described with reference to the drawings. explain.

In the embodiment of the present invention, a vibration parts feeder is applied as the electromagnetic vibration parts feeder.
In the bowl 1, a track is formed in a spiral shape on an inner peripheral wall portion thereof, and is connected to a lower base 2 by an inclined leaf spring 5 disposed at an equal angular interval. An electromagnet 3 is fixed to the base 2, and an electromagnetic coil 4 is wound around the electromagnet 3. The whole vibrating parts feeder is installed on the floor by the vibration isolating rubber 6.

A vibration pickup P is provided near the leaf spring 5. The pickup P is supported on the floor by a support (not shown). Which is connected to the resonance point tracking control circuit 7 according to the present invention via the electric line W _1. Further, an output is applied from the resonance point tracking control circuit 7 to the electromagnetic coil 4 of the electromagnet 3.

FIG. 2 shows a resonance point tracking control circuit 7 shown in FIG.
Of the variable frequency power supply 1
0, a phase detection circuit 11, a memory 15, and a constant amplitude control circuit 22. As shown in FIG. 1, an AC power supply 8 is connected to the variable frequency power supply 10 via a switch S. The output of the AC power supply 8 is supplied to a constant amplitude control circuit 22 and an amplifier 1.
2 is connected to the electromagnetic coil 4 of the electromagnet 3.
The output of the pickup P in FIG. 1 is connected to the increasing width 13 via electric lines W _1. This amplified output is supplied to the phase detection circuit 11. This phase detection circuit 11 includes:
Is further supplied the output of Zohaba 12, is supplied via the electric line W _3, the phase detection output variable frequency power supply 1
0 is supplied. This may be, for example, an inverter.

According to the embodiment of the present invention, the variable frequency power supply 10 is connected to the constant amplitude control circuit 22. The constant amplitude control circuit 22 is provided with a constant amplitude control circuit for giving a predetermined amplitude command. 21 are connected. Vibration pickup P
Is supplied via an electric wire W ₁ and an amplifier 13. Further, the constant amplitude control circuit 22 includes a circuit that changes the voltage linearly until a predetermined time is reached after the start of driving. Further, after the switch S is closed, the variable frequency power supply 10 is supplied with the resonance frequency supplied from the memory circuit 15 and stored after the previous drive, and this frequency is changed to the constant amplitude frequency control circuit 22 when the switch S is closed. To the amplifier 12 side. When the end time of the soft start is reached, the constant amplitude operation is performed on the constant amplitude frequency control circuit 22, and the variable frequency power supply 10 receives the output of the phase detection circuit 11 and performs the original resonance tracking control.

The phase detection circuit 11 according to the embodiment of the present invention performs phase detection by a method as shown in FIGS. This will be explained in detail in the following operation.

The configuration of the embodiment of the present invention has been described above. Next, this operation will be described.

When the switch S is closed, the AC power supply 8 is connected to the variable frequency power supply 10 and is driven. This output voltage is supplied to the electromagnetic coil 4 of the electromagnet 3 via the amplifier 12. Thereby, the bowl 1 of the vibrating parts feeder performs torsional vibration. The pickup P detects this vibration displacement, is amplified by the amplifier 13, and is applied to the phase detection circuit 11. On the other hand, it is supplied with the voltage applied to the electromagnetic coil 4 at this time.

FIG. 4A shows the temporal change of the applied voltage V. The electromagnetic coil 4 causes a temporary delay, and the current I flowing through the electromagnetic coil 4 changes as shown in FIG. 4B. Due to this current, an alternating magnetic attraction force is generated between the electromagnet 3 and the bowl 1, and the bowl 1 performs torsional vibration. As shown in FIG. In the case of a delay of 90 degrees, that is, if the vibration displacement S ₁ is positive at the zero cross point where the coil voltage V changes from positive to negative, as shown in FIG. 3, the phase difference φ at the resonance point ω ₀ (angular frequency) becomes 90 degrees, so ω
_The phase detection circuit 11 determines that the frequency should be increased below ₀ , and the output frequency of the variable frequency power supply 10 is increased. This is amplified by the amplifier 12 and the electromagnet 3
Bowl 4 with a higher frequency current
Vibrates. By approaching the resonance point ω _{0 from} the previous time, the amplitude increases. When the output frequency of the variable frequency power supply 10 further increases and finally exceeds ω ₀ and becomes higher than this, the relationship between the vibration displacement S ₂ and the coil voltage V becomes 270 degrees in phase difference as shown in FIGS. 4A and 4D. .

As is clear from the relationship between the frequency of the force and the phase difference between the vibration displacement shown in FIG. 3, the output frequency of the variable frequency power supply 10 is reduced because it has passed the resonance point ω ₀ . Note that FIG.
, C ₁ , C ₂ , and C ₃ represent viscosity coefficients of the vibration system, and C ₃ > C ₂ > C ₁ .

As described above, the output frequency of the variable frequency power supply 10 is increased or decreased, and finally the vibrating parts feeder is driven at the resonance frequency. In a spiral track (not shown) in the bowl 1 of the vibrating parts feeder, parts are aligned by a part aligning means so as to have a predetermined posture. It is supplied to the next process in this posture.

When the switch S is opened to stop the driving of the vibrating parts feeder, the output from the variable frequency power supply 10 is stopped, and the driving of the bowl 1 is stopped. The output frequency of the variable frequency power supply 10 before the switch S is turned off is stored in the nonvolatile memory 15. That is, the output frequency of the variable frequency 10 is stored in the memory 15 during driving or at regular intervals during driving.

When the switch S is closed to restart the driving of the vibrating parts feeder, the variable frequency power supply 10 is driven to output the resonance frequency stored in the memory 15 at this time. Therefore, the bowl 1 of the vibrating parts feeder is driven at a constant resonance frequency from the beginning. Therefore, there is no shock when shifting from the forced vibration to the resonance frequency as in the related art, and the power supply capacity can be reduced. Further, in the embodiment of the present invention, a soft start is performed.

In the following, the contents of the memory 15 are rewritten every time the driving is stopped and the driving is repeated, but the resonance frequency of the vibrating parts feeder fluctuates in units of one month or one year. Therefore, if the resonance frequency is obtained by controlling the tracking as in the past, a large amount of current must flow to shift from the forced oscillation to the resonance oscillation as described above. ,
Even if the fluctuation of the resonance frequency is large, the driving can be started at the previous resonance frequency, so that the vibration parts feeder can always be driven with a small power supply capacity without a shock.

With the above configuration, the resonance tracking control is performed after the end of the soft start. Therefore, the drive frequency is constant until the set time after the start of the drive. The parts in the bowl of the vibrating parts feeder are gradually raised, so that the parts in the bowl of the vibrating parts feeder do not rapidly advance to the aligning means, for example, the wiper, so that the parts are not clogged, and thereafter the original part aligning operation can be performed.

That is, as shown in FIG.
The driving frequency until time t ₀ is constant at f _1, the set time after t _0, but of performing the tracking control, increase or decrease the amount as shown is only, fixed in a short time the driving frequency f ₁ That is, it approaches the resonance point. Thereby the vibration displacement to the set time t ₀ as shown in FIG. 6 rises linearly from zero to a, after repeated increase and decrease of time after t _0, slight vibration displacement, a the predetermined vibration in a short time Becomes

Although the embodiment of the present invention has been described above, the present invention is, of course, not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the vibration parts feeder which performs linear torsional vibration has been described as the electromagnetic vibration feeder, but the present invention is also applicable to an elliptical vibration parts feeder. In this case, a vertical vibration plate spring, a horizontal vibration plate spring, a vertical vibration electromagnet and a horizontal vibration electromagnet are provided, and a predetermined position is provided between both vibration displacements obtained by both vibration forces. Although the elliptical vibration is performed with a phase difference, the present invention may be applied to one of the driving units, for example, the horizontal vibration force side.

The present invention is also applicable to a linear vibration feeder that performs linear vibration.

In the above-described embodiment, the drive frequency that is constant after the start of driving is the resonance frequency stored at the end of the previous drive. However, the present invention is not limited to this. May be used as a constant frequency.

[0027]

As described above, according to the method and the apparatus for controlling the drive of the electromagnetic vibration feeder of the present invention, the coil voltage is gradually increased after the start of the drive so that the vibration displacement can follow this. Even if the vibration displacement suddenly rises or the drive frequency fluctuates after the soft start, the original resonance tracking control of the electromagnetic vibration feeder can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a vibration parts feeder and a resonance point tracking control circuit for drive control according to an embodiment of the present invention.

FIG. 2 is a block diagram showing details of a resonance point tracking control circuit in FIG. 1;

FIG. 3 is a chart showing the relationship between the angular frequency of force and the phase difference between vibration displacement and force for illustrating the operation of the embodiment of the present invention.

FIG. 4 is a chart showing the operation of the embodiment of the present invention;
A is a time change of the coil voltage, B is a time change of the coil current, C is a time change when driven at a frequency lower than the resonance frequency of the vibration displacement, and D is a time change at a frequency higher than the resonance frequency. Is a temporal change of the vibration displacement of the radiator.

FIG. 5 is a chart showing a temporal change of a driving frequency showing an operation of a soft start according to the embodiment of the present invention.

FIG. 6 is a chart showing a temporal change of a vibration displacement showing an operation of the soft start.

FIG. 7 is a chart showing a temporal change of a coil voltage for soft start.

FIG. 8 is a chart showing a temporal change of a driving frequency after driving is started in the conventional example.

FIG. 9 is a chart showing a temporal change of a vibration displacement after the start of driving in the conventional example.

FIG. 10 is a chart showing a change in a resonance point according to a coil voltage of a vibrating parts feeder.

[Explanation of symbols]

 7 Resonance point tracking control circuit 10 Variable frequency power supply 11 Phase detection circuit 21 Amplitude command circuit 22 Constant amplitude control circuit

Claims (10)

[Claims] 1. A movable part and a base are connected by a spring, an electromagnet is attached to the movable part or the base, and a phase difference between a voltage applied to a coil of the electromagnet and a vibration displacement of the movable part is determined. Detecting and increasing or decreasing the frequency of the voltage applied to the coil so that the phase difference becomes 180 degrees so as to cause resonance oscillation, and at the start of driving, gradually increase the voltage to a predetermined height. In the drive control method for an electromagnetic vibration feeder that is made constant thereafter, the drive frequency is set to a constant frequency close to a resonance frequency until the voltage after the start of driving reaches the predetermined height. Drive control method for vibration feeder. 2. The drive control method for an electromagnetic vibration feeder according to claim 1, wherein the frequency of the voltage at the time of previous driving is stored, and the stored frequency is set to the constant frequency at the time of re-driving. 3. The drive control method for an electromagnetic vibration feeder according to claim 2, wherein the stored frequency of the voltage at the time of the previous drive is rewritten for each drive. 4. The detection of the phase difference according to whether the vibration displacement is positive or negative at a zero cross point of the voltage from negative to positive or from positive to negative.
The drive control method of the electromagnetic vibration feeder according to any one of the above. 5. A drive control method for an electromagnetic vibration feeder, wherein the voltage after the start of driving is gradually increased by linearly increasing the voltage at a predetermined gradient. 6. After the voltage reaches a predetermined height, the voltage is adjusted so that the movable portion vibrates at a predetermined amplitude, and the constant amplitude control is performed. Drive control method for electromagnetic vibration feeder. 7. A movable part and a base are connected by a spring, an electromagnet is attached to the movable part or the base, and a phase difference between a voltage applied to a coil of the electromagnet and a vibration displacement of the movable part is determined. The frequency of the voltage of the variable frequency power supply to be applied to the coil is increased or decreased so that the phase difference is detected by the phase difference detector and becomes 180 degrees, so that resonance oscillation occurs, and the voltage of the variable frequency power supply is In the drive control device of the electromagnetic vibration feeder, the voltage is gradually increased to a predetermined height at the start of driving by the voltage adjusting means receiving the voltage, and thereafter the voltage is fixed. The drive frequency of the electromagnetic vibration feeder is controlled to a constant frequency close to the resonance frequency until the height of the electromagnetic vibration feeder is reached. 8. The drive control device for an electromagnetic vibration feeder according to claim 7, wherein the frequency of the voltage at the time of previous driving is stored, and the stored frequency is set to the constant frequency at the time of re-driving. 9. The drive control device for an electromagnetic vibration feeder according to claim 8, wherein the stored frequency of the voltage at the time of the previous drive is rewritten for each drive. 10. The electromagnetic vibration according to claim 7, wherein the detection of the phase difference is performed depending on whether the vibration displacement is positive or negative at a zero cross point of the voltage from negative to positive or from positive to negative. Drive control device for feeder.