JP4066480B2 - Driving control method and apparatus for electromagnetic vibration feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drive control method and apparatus for an electromagnetic vibration feeder.
[0002]
[Prior art]
In this type of apparatus, the rising characteristics at the start of driving of an electromagnetic vibration feeder, for example, a vibration parts feeder, are performed as shown in FIG. That is, the voltage applied to the coil is increased almost linearly until time t ₀ . The voltage after t ₀ is made constant as a voltage for a predetermined amplitude. As a result, the parts in the bowl of the vibrating parts feeder, for example, chip-shaped parts, when the driving starts, the parts located in the vicinity of the wiper for making the single-layer plate-shaped parts, for example, the parts are smoothly downstream at the start of driving. A single layer is supplied to the side. However, the frequency of the bowl of the vibration parts feeder in the resonance tracking control changes as shown in FIG. That is, the frequency first increases from the frequency at the start of driving and then decreases, and after time t ₀ , the background as shown in the figure is shown. This is due to the resonance point change as shown in FIG. .
[0003]
FIG. 10 shows the frequency-width (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. For the same vibrating parts feeder, the voltage is increased, that is, the amplitude is increased for a certain frequency. The resonance frequency decreases as the amplitude increases. For example, as shown in FIG. 10, when the coil voltage is 70 volts, the resonance point is about 54.2 hertz, whereas when the coil voltage is 20 volts, it is about 55.8 hertz. This resonance point change is shown. This is because, as is well known, in a vibrating parts feeder, a bowl and a base are connected by inclined leaf springs arranged at equiangular intervals. Used as a spring. If the torsional amplitude is increased, the effective length for the vibration between the bolts fixing the upper and lower ends is increased. This reduces the spring constant of the leaf spring. That is. Resonance frequency decreases. This is considered to be a cause. FIG. 10 shows the transition of the resonance frequency when the coil voltage is changed from 20 volts to 70 volts as described above. Although this is an experimental example, as shown in FIG. 7, when the coil voltage is gradually changed to time t ₀ , the resonance frequency decreases as the amplitude increases during resonance. Although it depends on the speed, for example, a temporal change of the driving frequency as shown in FIG. 8 is observed. In the vicinity of the resonance point, the amplitude fluctuates greatly with a slight change in frequency. Although this is an unstable region, the vibration displacement of the bowl changes as shown in FIG. That is, at first, a change in the displacement of the vibration approximated to the increase in the coil voltage in FIG. 7 can be obtained, but the vibration displacement increases rapidly by time t ₀ due to the phenomenon shown in FIG. There is a time zone, and after the elapse of time t ₀ , it shows a so-called hunting phenomenon that rapidly decreases and increases, and makes control unstable.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electromagnetic vibration feeder drive control method and apparatus capable of performing desired resonance tracking control during driving while performing an original soft start. .
[0005]
[Means for Solving the Problems]
The above problem is that the movable part and the base are coupled by a spring, an electromagnet is attached to the movable part or the base, and the phase difference between the voltage applied to the coil of the electromagnet and the vibration displacement of the movable part is determined. The frequency of the voltage applied to the coil is increased / decreased so that the phase difference becomes 180 degrees, and resonance vibration is caused. At the start of driving, the voltage is gradually increased to a predetermined height. Then, in the drive control method of the electromagnetic vibration feeder that is made constant thereafter, the frequency of the voltage at the previous drive is stored, and at the time of re-drive, the drive is started until the voltage after the drive starts reaches the predetermined height The frequency is solved by the drive control method of the electromagnetic vibration feeder, wherein the stored frequency is a constant frequency close to the resonance frequency. Alternatively, the movable part and the base are coupled by a spring, an electromagnet is attached to the movable part or the base, and the phase difference between the voltage applied to the coil of the electromagnet and the vibration displacement of the movable part is detected. The voltage detected by the detector is caused to resonate by increasing or decreasing the frequency of the voltage of the variable frequency power supply to be applied to the coil so that the phase difference becomes 180 degrees, and the voltage receiving the voltage of the variable frequency power supply In the drive control device of the electromagnetic vibration feeder that gradually raises the voltage to a predetermined height at the start of driving by the adjusting means, and thereafter makes it constant, the frequency of the voltage at the previous driving is stored, the drive control device of an electromagnetic vibrating feeder to said voltage after start drive during re driving becomes to the predetermined height, characterized in that it has a constant frequency close to the frequency that the stored resonant frequency It is solved Te.
[0006]
With the above configuration, the coil voltage is changed as shown in FIG. 7 at a predetermined driving frequency at the start of driving. During this time, since the drive frequency is constant, a desired change in vibration displacement can be obtained, and, for example, a single layer supply of components can be performed smoothly without applying shocking transfer force to the 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 past, and the characteristic is always transferred at the resonance frequency following the temporal fluctuation of the resonance frequency, and this characteristic can be exhibited.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 are block diagrams of a resonance tracking control circuit according to an embodiment of the present invention. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0008]
In the embodiment of the present invention, a vibrating parts feeder is applied as an electromagnetic vibrating parts feeder, and in FIG. 1, a track is formed in a spiral shape on the inner peripheral wall portion in the bowl 1. Are coupled by inclined leaf springs 5 arranged at equal angular intervals. An electromagnet 3 is fixed to the base 2, and an electromagnetic coil 4 is wound around the electromagnet 3. The whole vibration parts feeder is installed on the floor by vibration-proof rubber 6.
[0009]
A vibration pickup P is disposed in the vicinity of the leaf spring 5. The pickup P is supported on the floor by a support (not shown). This 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.
[0010]
FIG. 2 shows details of the resonance point tracking control circuit 7 in FIG. 1, which mainly comprises a variable frequency power supply 10, 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, and the output thereof is an electromagnetic coil of the electromagnet 3 via a constant amplitude control circuit 22 and an amplifier 12. 4 is connected. Further, the output of the pickup P in FIG. 1 is connected to the amplifier 13 through the electric line W ₁ . This amplified output is supplied to the phase detection circuit 11. The output of the amplifier 12 is further supplied to the phase detection circuit 11 and supplied through the electric wire W ₃ , and this phase detection output is supplied to the variable frequency power supply 10. This may be an inverter, for example.
[0011]
According to the embodiment of the present invention, a constant amplitude control circuit 22 is connected to the variable frequency power supply 10, which is connected to an amplitude command circuit 21 for giving a predetermined amplitude command. Has been. Further, the output of the vibration pickup P is supplied through the electric line W ₁ and the amplifier 13. The constant amplitude control circuit 22 includes a circuit that linearly changes the voltage until a predetermined time is reached after the driving is started. Further, after the switch S is closed, the variable frequency power supply 10 is supplied with the resonance frequency stored from the memory circuit 15 after the end of the previous driving, and this frequency is set to the constant amplitude frequency control circuit 22 when the switch S is closed. To the amplifier 12 side. The constant amplitude frequency control circuit 22 reaches the soft start end time and performs a constant amplitude operation. The variable frequency power supply 10 receives the output of the phase detection circuit 11 and performs the original resonance tracking control.
[0012]
Further, 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.
[0013]
The configuration of the embodiment of the present invention has been described above. Next, this operation will be described.
[0014]
When the switch S is closed, the AC power source 8 is connected to the variable frequency power source 10 and is in a driving state. This output voltage is supplied to the electromagnetic coil 4 of the electromagnet 3 via the amplifier 12. Thereby, the bowl 1 of the vibration part 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, the voltage applied to the electromagnetic coil 4 at this time is supplied to this.
[0015]
FIG. 4A shows the temporal change of the applied voltage V, but a temporary delay is caused by the electromagnetic coil 4, and the current I flowing through the electromagnetic coil 4 changes as shown in FIG. 4B. This current generates an alternating magnetic attractive force between the electromagnet 3 and the bowl 1, and the bowl 1 undergoes torsional vibration. This vibration displacement, as shown in FIG. If the vibration displacement S ₁ is positive at the zero cross point where the coil voltage V changes from positive to negative when it is delayed by 90 degrees, the phase difference φ at the resonance point ω ₀ (angular frequency) is as shown in FIG. Since it is 90 degrees, the phase detection circuit 11 determines that the frequency should be increased smaller than ω ₀ , and the output frequency of the variable frequency power supply 10 is increased. This is amplified by the amplifier 12 and passed through the coil 4 of the electromagnet 3 to vibrate the bowl 1 with a higher frequency current. 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. .
[0016]
As apparent from the relationship between the phase of the force frequency and the vibration displacement in FIG. 3, the output frequency of the variable frequency power supply 10 is decreased because the resonance point ω ₀ is passed. In FIG. 3, C ₁ , C ₂ , and C ₃ represent the viscosity coefficients of the vibration system, and C ₃ > C ₂ > C ₁ .
[0017]
As described above, when the output frequency of the variable frequency power supply 10 is increased or decreased, this vibration part feeder is driven at the resonance frequency. In the spiral track (not shown) in the bowl 1 of the vibration part feeder, the parts are aligned by the parts aligning means so as to have a predetermined posture. This posture is supplied to the next process.
[0018]
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 lost and the driving of the bowl 1 is stopped. The non-volatile memory 15 stores the output frequency of the variable frequency power supply 10 before the switch S is turned off. That is, the output frequency of the variable frequency 10 is stored in the memory 15 during driving or every fixed time during driving.
[0019]
When the switch S is closed to start driving the vibration parts feeder again, the variable frequency power source 10 is driven to output the resonance frequency stored in the memory 15 at this time. Accordingly, 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 prior art, and the power source capacity can be reduced. Further, in the embodiment of the present invention, soft start is performed.
[0020]
Hereinafter, every time the driving stop and the driving start are repeated, the contents of the memory 15 are rewritten every time the driving is stopped. However, the resonance frequency of the vibrating parts feeder varies in units of one month and one year. Therefore, if the resonance frequency was obtained by tracking control as in the past, a large amount of current must be passed to move from forced vibration to resonant vibration as described above. Since the drive can be started at the previous resonance frequency even if the fluctuation of the resonance frequency is large, the vibration parts feeder can always be driven with a small power supply capacity without a shock.
[0021]
With the above configuration, the resonance tracking control is performed after the soft start end time. Therefore, the vibration displacement gradually increases as desired at the constant drive frequency, that is, the resonance frequency in this embodiment until the set time after the start of the drive. Therefore, the parts in the bowl of the vibrating parts feeder are rapidly advanced to the aligning means, for example, the wiper, and the parts are not clogged, and the original parts aligning operation can be performed thereafter.
[0022]
That is, after the start of driving, as shown in FIG. 5, 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 a slight There is a constant drive frequency f ₁ in a short time, that is, the resonance point is approached. 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 It becomes.
[0023]
The embodiment of the present invention has been described above. Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.
[0024]
For example, in the above embodiment, the vibration parts feeder that performs linear torsional vibration is described as the electromagnetic vibration feeder, but the present invention can also be applied to an elliptical vibration parts feeder. In this case, it has a vertical vibration plate spring, a horizontal vibration plate spring, a vertical vibration electromagnet, and a horizontal vibration electromagnet, and a predetermined position 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 excitation force side.
[0025]
The present invention can also be applied to a linear vibration feeder that performs linear vibration.
[0026]
In the above embodiment, the drive frequency that is constant after the start of driving is the resonance frequency that is stored at the end of the previous drive. However, the present invention is not limited to this, and the resonance frequency in the vicinity of the expected resonance frequency is constant. You may use as a frequency to do.
[0027]
【The invention's effect】
As described above, according to the drive control method and apparatus of the electromagnetic vibration feeder of the present invention, the coil voltage can be gradually increased after the start of driving so that the vibration displacement can follow this. Even if the driving frequency suddenly rises or the driving frequency fluctuates after the soft start is completed, 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 part feeder and a resonance point tracking control circuit for driving 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 of the phase difference between the angular frequency of force and the vibration displacement 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, where A is a temporal change in coil voltage, B is a temporal change in coil current, and C is driven at a frequency lower than the resonance frequency of vibration displacement. , D is the time change of the vibration displacement when driven at a frequency higher than the resonance frequency.
FIG. 5 is a chart showing a temporal change in drive frequency showing the effect of soft start according to the embodiment of the present invention.
FIG. 6 is a chart showing a temporal change in vibration displacement showing the effect of the soft start.
FIG. 7 is a chart showing temporal changes in the coil voltage for soft start.
FIG. 8 is a chart showing temporal changes in drive frequency after the start of driving in the conventional example.
FIG. 9 is a chart showing temporal changes in vibration displacement after the start of driving in the conventional example.
FIG. 10 is a chart showing the change of the resonance point due to the coil voltage of the vibration part 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 (8)

A movable part and a base are coupled by a spring, an electromagnet is attached to the movable part or the base, a phase difference between a voltage applied to a coil of the electromagnet and a vibration displacement of the movable part is detected, and the The frequency of the voltage applied to the coil is increased / decreased so that the phase difference becomes 180 degrees, and the vibration is caused to resonate. At the start of driving, the voltage is gradually increased to a predetermined height, and then constant. In the drive control method of the electromagnetic vibration feeder, the frequency of the voltage at the previous drive is stored, and the drive frequency is stored until the voltage after starting the drive reaches the predetermined height at the time of re-drive . A drive control method for an electromagnetic vibration feeder, wherein the frequency is a constant frequency close to a resonance frequency. 2. The drive control method for an electromagnetic vibration feeder according to claim 1, wherein the stored frequency of the voltage at the previous drive is rewritten for each drive. The electromagnetic vibration feeder according to claim 1, wherein the phase difference is detected based 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. Control method. 2. The drive control method for an electromagnetic vibration feeder according to claim 1, wherein the voltage after the start of driving is increased gradually by linearly increasing at a predetermined gradient. 2. The constant amplitude control according to claim 1, wherein after the voltage reaches a predetermined height, the voltage is controlled so as to vibrate the movable part with a predetermined amplitude. Drive control method for electromagnetic vibration feeder. A movable part and a base are coupled 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 detected by a phase difference detector. Voltage adjusting means for detecting and causing resonance oscillation by increasing or decreasing the frequency of the voltage of the variable frequency power supply to be applied to the coil so that the phase difference is 180 degrees, and receiving the voltage of the variable frequency power supply Thus, in the drive control device of the electromagnetic vibration feeder, the voltage is gradually increased to a predetermined height at the start of driving, and is made constant thereafter. The drive control device for an electromagnetic vibration feeder, wherein the stored frequency is set to a constant frequency close to a resonance frequency until the voltage after the drive starts reaches the predetermined height. 7. The drive control device for an electromagnetic vibration feeder according to claim 6, wherein the stored frequency of the voltage at the previous drive is rewritten for each drive. The drive control device for an electromagnetic vibration feeder according to claim 6 or 7, wherein the phase difference is detected depending on whether the vibration displacement is positive or negative at a zero cross point from negative to positive or from positive to negative. .

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