JP2000317397A - Method and apparatus for real-time control of electromagnetic type oscillating body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an electromagnetic type oscillating body at real-time to an input signal and to oscillate/control the oscillating body accurately by making it proportional correctly to the input signal. SOLUTION: A simulation circuit 2 for outputting a signal close to the free motion of an electromagnetic type oscillating body to an input signal is installed independent of a practical driving circuit. The simulation circuit 2 produces signals of acceleration, speed, and displacement corresponding to the free motion of the oscillating body from the input signal. In these signals, the mass, friction and distortion by spring force of the oscillating body are compensated/corrected by a compensation/correction operation level conversion circuit. The compensated/corrected signal is current-amplified and supplied to the coil of the oscillating body, and the oscillating body is made correctly proportional to the input signal at real-time to the input signal and oscillated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for driving and controlling an electromagnetic vibrator such as an audio speaker and a vibration tester in real time.

[0002]

2. Description of the Related Art An electromagnetic vibrating body such as an audio speaker or a vibration tester has a magnetic field line of a fixed magnetic field, and a coil is supported on a suspension so that current directions are orthogonal to each other. By flowing, the speaker cone and the sample stage connected to the coil and the sample stage move in a certain range. In the case of an audio amplifier and a speaker, the output (voltage) relative to the input of the amplifier, that is, the input of the speaker is designed to have low distortion by a feedback loop. In an audio system, sound is converted to voltage by a microphone and immediately input to an amplifier and speakers. Alternatively, it is input to an amplifier speaker through various recording media. When considering an ideal audio system, the output waveform when the sound of the sound source is input to the microphone and its output waveform is input, and the microphone output is input to the amplifier and the speaker is driven to generate sound and the sound is input to another microphone. As long as the waveform is the same, such an ideal audio system has not yet emerged.

The purpose of using a vibration tester is to apply a vibration acceleration to a sample and to test the resonance point, durability and the like of the sample. For the waveform of the vibration acceleration, there are a method of sweeping the frequency with a sine wave monotone, and a method of comparing and verifying the input spectrum of the random waveform and the output spectrum of the sample. In the case of a monotone sine wave, adjust the input signal while monitoring the average value, effective value, peak value, etc. to reduce the effect of the resonance frequency ignoring the phase shift, and adjust the output acceleration to the target value. I have. In addition, in the case of random excitation, check the correlation between the input spectrum waveform and the output spectrum waveform, design a filter for the random input waveform to be the same as the original input waveform spectrum, and input the signal waveform through the filter In general, a method is used in which the output waveform spectrum approaches the input waveform spectrum.

[0004]

It is common that both a vibration tester and an audio speaker generate a driving force by a force acting on a coil by a magnetic field and a current flowing through the coil. If the strength of the magnetic field is constant, the magnitude of the driving force is proportional to the magnitude of the current flowing through the coil. Both the coil and sample stage of the vibration tester, the voice coil and the speaker cone of the speaker have a finite mass. The input impedance of the coil changes greatly by moving in the space.

In addition, internal loss due to deformation of the suspension
For loss due to resistance and friction resistance and deformation of speaker cone
Speed loss such as internal loss. Driving force (F: f
orce), acceleration (α: acceleratio)
n) and mass (M: mass) are free from friction and resistance
Free motion (Free Run) with no change in angular momentum
If F = Mα, the vibration is unequal acceleration, so the time is t
Assuming that α = φ (t), the velocity (V: Veloc)
ity) is: V = ∫φ (t) dt + V₀  Is represented by

[0006] The initial velocity _{V 0} is V due to the restoring force by the support apparatus
₀ may be set to 0. This means that the speed is linearly integrated with respect to the time of the acceleration α. Regarding the displacement (D: Displacement), D = F (V) = {f (V) dV = {f} φ (t)} φ ′
(T) dt, which means that the acceleration is quadratic integrated with respect to time t. Here, if there is no friction or restoring force of the support mechanism for the coil, the sample stage, and the speaker cone, there is no obstacle to the vibration, and there is no influence on the motion of the vibrating body, that is, if free motion (FreeRun) is performed. For a vibrator, it is easy to obtain an acceleration α proportional to the input.

Since the sound pressure is proportional to the square of the speed of the speaker cone, if the input is squared and differentiated and input, a sound pressure proportional to the input can be obtained. However, in reality, it was impossible to eliminate the distortion and loss of the driving force caused by the restoring force of the suspension due to the displacement and the stiffness of the speaker cone. In addition, since factors such as distortion and loss include a plurality of different dimensions with respect to time, it is meaningless to detect the output with a sensor or the like and feed it back to the input. This makes the existence of the resonance frequency and the drive control in real time impossible. That is, the reason is that “an output proportional to the input cannot be obtained”.

As a countermeasure against this problem, there is a method of incorporating a function for compensating for distortion, loss, and change in impedance into a drive system itself composed of a speaker, a vibrator, and an amplifier, so that the drive system is close to a free motion (Free Run). Although it is conceivable, in practice, this system becomes unstable as it approaches a state closer to free motion, and easily causes runaway such as hunting. How to control in a stable and free motion state? If we consider again what a feedback loop is made and controlled, if the dimensions are the same, the output is fed back to the input, that is, the input becomes the reference of the output.

However, if the output cannot be based on the input when the dimensions are different, what should be based on the input? If the direct input cannot be used as a reference, the operation required for the input may be performed to produce samples of the same dimension, which may be regarded as inputs of the same dimension, and the output may be compensated based on the input. That is, in the case of a vibration tester or audio speaker, the simulation circuit is designed to simulate free motion in a form close to the theoretical value, predict in advance the speed and loss or distortion associated with displacement, and perform appropriate compensation and correction at appropriate timing. Uncertain factors such as drive system drift do not enter and stable and accurate correction and compensation can be performed. An object of the present invention is to solve the above problems.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides an electromagnetic type vibrating body which is arranged so as to be perpendicular to the magnetic field lines of a fixed magnetic field. In a control method for generating a force,
In order to make the vibration of the electromagnetic vibrator proportional to the input signal as accurately as possible, a simulation circuit that outputs a signal close to the free motion of the vibrator with respect to the input signal is installed independently of the actual drive circuit. Acceleration,
The output signals of speed and displacement are used for compensation and correction of distortion due to the mass, friction, and spring force of the vibrating body.The compensated and corrected signal is amplified and supplied to the coil of the vibrating body. In this way, the vibration is made in real time in direct proportion to the input signal.

Further, the present invention provides an electromagnetic vibrator for generating an oscillating force in a coil by applying an oscillating current to a coil of the electromagnetic vibrator which is disposed so as to be orthogonal to a magnetic field line of a fixed magnetic field. In the control device, a simulation circuit that outputs acceleration, velocity, and displacement signals corresponding to free motion with respect to an input signal for vibrating the coil,
A compensation / correction operation and level conversion circuit for compensating and correcting loss, distortion, and the like of the vibrator for the output signal of the simulation circuit and outputting a vibrator drive signal; And a current amplification / current output circuit for amplifying the current of the output signal of the circuit and supplying the amplified current to the coil of the electromagnetic vibrating body to drive the coil to vibrate.

Further, the present invention provides an acceleration signal generating circuit for extracting a change in an input signal as an acceleration signal, a speed signal generating circuit for linearly integrating the acceleration signal with respect to time and extracting as a speed signal, And a displacement signal generating circuit that performs quadratic integration of the signal with respect to time and extracts the signal as a displacement signal. Also, the present invention provides the compensation / correction calculation level conversion circuit, wherein the first volume resistance is set to a value corresponding to the mass of the vibrating body;
A second volume resistance set to a value corresponding to a frictional force acting on the vibrating body, and a third volume resistance set to a value corresponding to a spring force acting on the vibrating body; Compensating a signal by the first volume resistor, compensating a speed output signal of the simulation circuit by the second volume resistor,
The displacement output signal of the simulation circuit is corrected by the third volume resistor.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, when an input signal such as a voice signal or a vibration signal is input to a simulation circuit 2, the simulation circuit 2 analyzes the input signal into an acceleration signal, a velocity signal, and a displacement signal and outputs them. These acceleration signal, speed signal, and displacement signal indicate free motion of the vibrating body with respect to the input. The output of the simulation circuit 2 is input to a compensation / correction calculation and level conversion circuit 4, where the acceleration signal is compensated for the mass of the vibrating body, and the speed signal is compensated for the friction loss of the vibrating body. For the displacement signal, the distortion is corrected by the restoring force acting toward the neutral point due to the displacement of the vibrating body, that is, the distortion is corrected by the spring force.

Further, after the compensation / correction signals of the respective signals are added, level conversion is performed, and the resultant signal is input to a current amplification / current output circuit 6 at a subsequent stage. The audio speaker 8 or the vibration tester 10 is driven by the current amplification / current output circuit 6. Next, the simulation circuit 2 will be described with reference to FIG. Input terminal T of simulation circuit 2
The input signal input from 1 is passed through the operational amplifier A1 to ACC
It is output to the output line as an acceleration signal. The operational amplifier A1 changes the output impedance, and the output side is connected to an integrating circuit including a volume resistor VR1, resistors R1, R2, and a capacitor C1.

The input signal input from the input terminal T1 is supplied as an acceleration signal to an integrating circuit via an operational amplifier A1, where it is integrated, the polarity is converted by an operational amplifier A3, and the resultant signal is output as a speed signal to a VEL output line. You. The speed signal is supplied to an integrating circuit composed of a volume resistor VR2, a resistor R3, and a capacitor C2, where it is integrated, and the polarity is converted by an operational amplifier A5 to DIS.
It is output to the P output line as a displacement signal. The acceleration signal, the velocity signal, and the displacement signal appearing on the output lines ACC, VEL, DISP of the simulation circuit 2 correspond to the free movement of the audio speaker 8 or the vibrating body of the vibration tester 10.

Next, a compensation / correction operation and level conversion circuit 4
Will be described with reference to FIG. The acceleration signal ACC from the simulation circuit 2 is supplied to the volume resistor VR3
, The speed signal VEL is supplied to a volume resistor VR4, and the displacement signal DISP is supplied to a volume resistor VR5. The volume resistance VR3 is set to a value corresponding to the mass of the vibrating body that prevents free vibration of the vibrating body.
Losses due to the mass of the vibrator are compensated. The volume resistance VR4 is set to a value corresponding to a frictional force acting on the vibrating body that hinders the free movement of the vibrating body.
R4 compensates for the loss of velocity motion of the vibrating body due to the frictional force of the vibrating body.

The volume resistance VR5 is set to a value corresponding to a spring force acting on the vibrating body, and the displacement of the vibrating body due to the spring force is corrected by the volume resistance VR5. The acceleration, velocity, and displacement signals compensated for and compensated for loss and distortion due to mass, friction, and spring force are supplied to an operational amplifier A6, where they are added. Operational amplifier A
6 are operational amplifiers A7, A8, A9, A10, A
The signal level is sent to a level conversion circuit composed of the amplifier 11 and A12, where the signal level is converted so that the compensation / correction operation output of the operational amplifier A6 matches the current amplification / current output circuit 6 in the subsequent stage. The output signal of the compensation / correction calculation and level conversion circuit 4 is output to a current amplification / current output circuit 6 where the output signal is subjected to current amplification and the current output is changed to a load 8.
Or 10 to drive the load 8 or 10, that is, the electromagnetic vibrator.

[0018]

According to the present invention, the electromagnetic vibrating body can be controlled in real time with high accuracy.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a system block of the present invention.

FIG. 2 is a simulation circuit diagram.

FIG. 3 is a circuit diagram of a compensation / correction calculation and level conversion circuit.

FIG. 4 is a current amplification / current output circuit diagram.

[Explanation of symbols]

 2 Simulation circuit 4 Compensation / correction calculation and level conversion circuit 6 Current amplification / current output circuit 8 Audio speaker 10 Vibration tester

Claims (4)

[Claims] A control method for generating an oscillating force in a coil by applying an oscillating current to a coil of an electromagnetic vibrating body disposed so as to be orthogonal to a magnetic line of magnetic field of a fixed magnetic field. In order to make the body vibration proportional to the input signal as accurately as possible, a simulation circuit that outputs a signal close to the free motion of the vibrating body with respect to the input signal is installed independently of the actual drive circuit, and the acceleration and speed of the simulation circuit The output signal of displacement is used for compensation and correction of distortion due to the mass, friction, and spring force of the vibrating body, and the compensated and corrected signal is amplified and supplied to the coil of the vibrating body, and the vibrating body is supplied with respect to the input signal. A real-time control method of an electromagnetic vibrating body, characterized in that vibration is performed in real time in exactly proportion to an input signal. 2. An electromagnetic vibrating body control device for generating an oscillating force in a coil by applying an oscillating current to a coil of the electromagnetic vibrating body disposed so as to be orthogonal to a magnetic field line of a fixed magnetic field, A simulation circuit that outputs acceleration, velocity, and displacement signals corresponding to free motion with respect to an input signal for vibrating the coil, and a mass, friction, and spring force of the vibrating body with respect to an output signal of the simulation circuit. A compensation / correction calculation and level conversion circuit for compensating and correcting the loss distortion and outputting a vibrating body drive signal; and a current amplifying the output signal of the compensation / correction calculation and level conversion circuit and amplifying the current amplified by the coil of the electromagnetic vibration body. A real-time control device for an electromagnetic vibrating body, comprising: a current amplification / current output circuit that supplies and vibrates and drives the coil. 3. The simulation circuit includes: an acceleration signal generation circuit that extracts a change in an input signal as an acceleration signal; a speed signal generation circuit that linearly integrates the acceleration signal with respect to time and extracts a speed signal; 3. A method and apparatus for real-time control of an electromagnetic vibrating body according to claim 1, further comprising a displacement signal producing circuit for performing quadratic integration and extracting the displacement signal as a displacement signal. 4. The compensation / correction operation level conversion circuit,
A first volume resistance set to a value corresponding to the mass of the vibrating body, a second volume resistance set to a value corresponding to a frictional force acting on the vibrating body, and a value corresponding to a spring force acting on the vibrating body A third volume resistor set to, the acceleration output signal of the simulation circuit is compensated by the first volume resistor, the speed output signal of the simulation circuit is compensated by the second volume resistor, 3. The real-time control apparatus for an electromagnetic vibrating body according to claim 2, wherein the displacement output signal of the simulation circuit is corrected by the third volume resistance.