JPH11139533A - Self-excited resonant vibrating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost, high-performance electromagnetic feeder utilizing the vibration by the attracting force of an electromagnet and restoring force of a spring to convey powder, accurately applying a resonance phenomenon corresponding to the natural oscillation characteristic, miniaturizing the electromagnet, and capable of controlling quick acceleration, quick stop, and high-precision conveyance quantity. SOLUTION: This self-excited resonant vibrating device utilizing the attracting force of an electromagnet 1 and the restoring force of a spring 3 is provided with an acceleration sensor 4 detecting the acceleration of a vibrated body 2 and negatively feeding it back to an acceleration command, arithmetic means 7, 8 applying the PI operation and square root operation to the deviation between the acceleration command and the acceleration detected by the acceleration sensor 4 to obtain the current command width, and a current control power amplifier 13 feeding a current to the electromagnet 1 based on the product of the phase of the vibration speed obtained by integrating the acceleration detected by the acceleration sensor 4 and the current command width obtained by the arithmetic means 7, 8. The acceleration of the vibration of the electromagnet 1 is controlled accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-excited resonance type vibration device for transporting a granular material utilizing vibration caused by an attractive force of an electromagnet and a restoring force of a spring.

[0002]

2. Description of the Related Art A self-excited resonance type vibration device for driving an electromagnetic feeder is disclosed in Japanese Patent Publication No. Hei 5-74435. The configuration of the control system is shown in the block diagrams of FIG. 10 and FIG.

In FIG. 10, when a target amplitude is given as a command, a deviation from the detected amplitude is calculated by a subtractor 37, amplified by a control amplifier 31, amplified by a power amplifier 32 having a variable amplification factor, and amplified by an electromagnet 33. Is supplied with power. The amplitude of the electromagnet is detected by an amplitude detector 34, and the phase shifter 35 has a power amplifier 32 having a leading phase of 90 degrees and a variable amplification degree.
To give the electromagnet 33 an exciting force having a natural frequency. The output of the amplitude detector 34 is provided to an absolute value calculation circuit 36, and the subtractor 37 negatively feeds back to the target amplitude.

[0004] On the other hand, in FIG. 11, a target value is given as a speed, and an electromagnet 33 detected by an amplitude detector 34.
Is converted into a voltage by the f / V converter 38, multiplied by the absolute value of the vibration calculated by the absolute value calculation circuit 36 by the multiplier 39, and negatively fed back to the target speed. Other configurations and operations are the same as those in FIG.

[0005]

However, FIG.
In addition, the conventional self-excited resonance type vibration device shown in FIG. 11 controls the amplitude of the output AC of the power amplifier 32 having the variable amplification so that the amplitude decreases as the deviation increases, and conversely, increases as the change decreases. Only the qualitative relationship that the operation is performed is unclear, the theoretical necessity of operation is unclear, and the response speed is also insufficient.

The problem to be solved by the present invention is to precisely apply a resonance phenomenon corresponding to a natural vibration characteristic to an electromagnetic feeder that conveys powder by utilizing vibration caused by an attractive force of an electromagnet and a restoring force of a spring. , Enabling the downsizing of electromagnets, rapid excitation, quick stop, high-accuracy transport amount control, etc.
An object of the present invention is to provide a low-cost, high-performance electromagnetic feeder device.

[0007]

According to a first aspect of the present invention, there is provided a vibrating mechanical device utilizing an attractive force of an electromagnet and a restoring force of a spring to detect an acceleration of a vibrating body. An acceleration sensor that negatively feeds back the acceleration command, a calculation unit that obtains a current command amplitude by performing a PI calculation and a square root calculation on a deviation between the acceleration command and the acceleration detected by the acceleration sensor, and an acceleration sensor that is detected by the acceleration sensor. A current control power amplifier that supplies a current to the electromagnet based on the product of the phase of the vibration velocity obtained by integrating the acceleration and the current command amplitude obtained by the arithmetic means. It is characterized in that acceleration of vibration is controlled.

According to a second aspect of the present invention, in a vibrating mechanical device utilizing an attractive force of an electromagnet and a restoring force of a spring, an acceleration of a vibrated body is detected, and a detection speed which is an integral value of the acceleration is detected. An acceleration sensor that negatively feeds back the speed command; a calculating unit that obtains a current command amplitude by performing a PID calculation and a square root calculation of a deviation between the speed command and the detected speed; and a vibration speed obtained by integrating the detected acceleration. A current control power amplifier that supplies a current to the electromagnet based on a product of a phase and a current command amplitude obtained by the calculation means is provided to control a transport amount of the granular material.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on embodiments shown in the drawings. FIG. 1 shows the configuration of an embodiment of the first means of the present invention. In the figure, 1 is an electromagnet, 2 is a vibrating body, 3 is a spring, 4 is an acceleration sensor, 5 is an absolute value calculation circuit, 6 is a subtractor, 7 is a PI calculator, 8 is a square root calculator, 9 is a comparator, 10 Is 90 ° (π
/ 4) an integrator for generating a delayed phase, 11 is a constant amplitude sine wave shaping circuit, 12 is a multiplier, and 13 is a current control power amplifier.

In this embodiment, the absolute value of the acceleration of the vibrating body 2 is negatively fed back to the acceleration command, the error is calculated by PI and the square root is obtained, and the value of the constant amplitude velocity phase obtained by integrating the acceleration is obtained. To obtain a product and obtain a force proportional to this value, the electromagnet 1 is energized using the current control power amplifier 13.

The means for controlling the natural vibration of the mechanical system in this embodiment will be described. The attractive force of the electromagnet 1 is F
(N), the mass of the vibrating body 2 is M (kg), the spring constant of the spring 3 is K (N / m), and the damping coefficient of the vibration is D (N / m
/ S) and the displacement is x (m), the suction force F is represented by the following equation as a general equation.

F = M (d ² x / dt ² ) + D (dx / dt) + Kx (1) By modifying this, the following equation is obtained. F−D (dx / dt) = M (d ² x / dt ² ) + Kx (2) The right side of the equation (2) is a sustained natural vibration having a constant amplitude.

Therefore, the left side is FD (dx / dt)
What is necessary is just to control F so that = 0. That is, if the attraction force F of the electromagnet is controlled by the phase of the velocity vector by an amount that eliminates the vibration damping force, it is possible to realize constant amplitude control that resonates with the natural vibration of the mechanical system.

Since the damping of the mechanical vibration depends on the damping constant D, when the product of the velocity phase and the value of the PI operation is given to the opposite polarity equivalent to D, the damping is canceled and the natural frequency of the vibration amplitude invariable is obtained. available. Therefore, the natural frequency and the electromagnet current change according to changes in the load mass M and the damping constant D.

From the right side = 0 of the equation (2), the natural frequency f =
(1 / 2π) (K / M) ^1/2 (HZ) is obtained, and the electromagnet current I = (GD / K
_F ) (M / K) ^1/2 (A).

Where G: acceleration (m / s ² ), D: damper constant (N / m / s), K _F : force coefficient of electromagnet (N / m / s 2)
A).

It should be noted that the electromagnet attractive force F is determined by the current I and the distance x.
In relation ^{_{to, F ≒ (μ 0 AN 2}} /2) (I / x) 2
Is nonlinear. Here, μ ₀ : vacuum permeability (H /
m), A: magnetic pole sectional area (m ² ), N: number of coil turns.

Therefore, to stabilize the control, the PI
The output is square-rooted to perform linearization control. For this purpose, the electromagnet attractive force is controlled by the product of the square root calculation value and the phase of the vibration velocity vector.

A description will be given of the speed phase calculating means.
The detection voltage of the acceleration sensor 4 is converted into a square wave voltage by a comparator (COM) 9 and converted into a triangular wave with a 90 ° phase delay by an integrator 10, and then a constant amplitude sine wave shaping circuit (function generator)
In step 11, the waveform is shaped into a sine waveform having a constant peak voltage of 10 v, and the speed phase is calculated.

Next, the configuration of the second means of the present invention is shown in FIG. The difference from FIG. 1 is that the PI calculator 7 is changed to a PID calculator 15 and the value obtained by integrating the acceleration detected by the acceleration sensor 4 with the integrator 14 and converting it into velocity is calculated as an absolute value. The two points are that the absolute value is calculated by the circuit 5, the deviation from the speed command is obtained by the subtractor 6, and is output to the PID calculator 15. This makes it possible to control the transport amount of the granular material.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the first means of the present invention will be described with reference to FIGS. In this embodiment, the acceleration command is given by the variable resistor 21. For switching between high speed and low speed (about 1:10), a resistive voltage dividing circuit 22 and a changeover switch 23 are provided to perform rapid oscillation and rapid braking. P (proportional) gain adjustment is adjusted by the variable resistor 24. With the start / stop switch 25,
Starts oscillation oscillation and stops coasting. The square root calculator 8 is composed of a function generator as shown in FIG.
The square root of the output of the PI calculator is calculated by the broken line approximation shown in FIG.

The acceleration of the vibrating body 2 is detected by the acceleration sensor 4 and passed through a high frequency band of 1 Hz or more by the amplification and high-pass filter 26 and amplified.

In the comparator 9, the output of the amplifying and high-pass filter 26 is a square wave of ± constant amplitude. The output of the comparator 9 is converted into a triangular wave delayed by 90 ° by the integrator 10 so as to have the phase of the vibration velocity. The output of the integrator 10 is shaped into a sine wave having a constant peak voltage of 10 V by a constant amplitude sine wave shaping function generator 11 shown in FIG.

The output of the amplification and high-pass filter 26 is subjected to full-wave rectification or full-wave rectification by a sample-and-hold circuit 27 shown in FIG.

The multiplier 12 multiplies the output voltage of the square root calculator 8 by the output voltage of the function generator 11. Multiplier 1
2 uses, for example, AD534.

FIG. 7 shows an outline of a current control power amplifier (PWM system). In response to the current command, the current detection is negatively fed back, the error is amplified by the control amplifier 28, and its output is
A PWM pulse obtained by comparing with a 0 kHz triangular wave is given to transistors TR1 and TR2 to be turned ON / OFF, and a current proportional to the command is given to electromagnet 1.

FIG. 8 shows the acceleration (a), the controller output (b), the current (c), the voltage () at the time of switching from the low speed to the high speed and at the time of the switching from the high speed to the low speed. It is a waveform diagram of an oscillograph showing d). As can be seen from this figure, the acceleration of the vibration responded to the acceleration command in about 0.2 seconds, and high-performance control was realized.

Next, an embodiment of the transport amount control will be described. In this embodiment, only the following two points need to be added to FIG. The addition of the differential control circuit 29 shown in FIG. 9 The integrator 14 (see FIG. 2) is added to change the acceleration to the amplitude of the velocity, and the amplification and high-pass filter 2 shown in FIG.
6 is integrated and input to the full-wave rectification or sample-and-hold circuit 27. The experimental results of this method were also good.

In the digital control, if the above-mentioned analog system is digitized, (a) the full-wave rectification operation is changed to a sample-and-hold operation, whereby a higher-speed response is possible. (B) There is no miscalculation of drift in integration, and the accuracy is high. (C) The function generator operation also becomes highly accurate. (D) The operation of the expensive multiplier can be performed at low cost. There are many advantages.

[0030]

As described above, according to the present invention, the size of the electromagnet can be reduced and the speed of the electromagnet can be reduced by accurately applying the resonance phenomenon corresponding to the natural vibration characteristic of the vibration caused by the attractive force of the electromagnet and the restoring force of the spring. It is possible to realize a low-cost, high-performance electromagnetic feeder device that enables vibration, quick stop, high-accuracy transport amount control, and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an acceleration control method according to the present invention.

FIG. 2 is a block diagram illustrating a transport amount control method according to the present invention.

FIG. 3 is a circuit diagram showing an embodiment of the acceleration control of the present invention.

FIG. 4 is a diagram showing an example of a circuit configuration of a function generator of the present invention and its characteristics.

FIG. 5 is a circuit diagram showing another example of the function generator of the present invention.

FIG. 6 is a circuit diagram showing an example of a full-wave rectifier circuit of the present invention.

FIG. 7 is a circuit diagram showing an example of a current control PWM inverter according to the present invention.

FIG. 8 is a waveform diagram of a response to an acceleration command in the present invention.

FIG. 9 is a circuit diagram showing a differential control circuit unit in the embodiment of the transport amount control of the present invention.

FIG. 10 is a block diagram showing a vibration amplitude control method in a conventional self-excited resonance type vibration device.

FIG. 11 is a block diagram showing a transport speed control method in a conventional self-excited resonance type vibration device.

[Explanation of symbols]

Reference Signs List 1 electromagnet, 2 vibrator, 3 spring, 4 acceleration sensor, 5 absolute value calculation circuit, 6 subtractor, 7 PI calculator, 8 square root calculator, 9 comparator, 10 integrator, 1
1 constant amplitude sine wave shaping circuit, 12 multiplier, 13 current control power amplifier, 14 integrator, 15 PID calculator, 21 variable resistor, 22 high-speed low-speed voltage dividing circuit, 23
High-speed low-speed switch, 24 gain adjuster, 25
Start / stop switch, 26 amplification and high-pass filter, 27 full-wave rectification or sample-and-hold circuit, 28
Control amplifier, 29 Differential control circuit

Claims (2)

[Claims] 1. A vibrating mechanical device using an attractive force of an electromagnet and a restoring force of a spring, comprising: an acceleration sensor that detects acceleration of a vibrated body and negatively feeds back an acceleration command; A calculating means for obtaining a current command amplitude by performing a PI calculation and a square root calculation on a deviation from the detected acceleration; a phase of a vibration velocity obtained by integrating the acceleration detected by the acceleration sensor; A current control power amplifier for supplying a current to the electromagnet based on a product of the current command amplitude and the current command amplitude, thereby controlling acceleration of vibration of the electromagnet. 2. A vibrating mechanical device using an attractive force of an electromagnet and a restoring force of a spring, wherein the acceleration sensor detects an acceleration of a vibrating body and negatively feeds back a detected speed, which is an integral value of the acceleration, to a speed command. A calculating means for obtaining a current command amplitude by PID calculation and a square root calculation of a deviation between the speed command and the detected speed; and a phase of a vibration speed obtained by integrating the detected acceleration and the calculating means. A self-excited resonance type vibration device, comprising: a current control power amplifier that supplies a current to the electromagnet based on a product of the current command amplitude and a current control power amplifier.