JP4475550B2 - Method and apparatus for real-time control of electromagnetic vibrator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for driving and controlling electromagnetic vibrators such as audio speakers and vibration testers in real time.
[0002]
[Prior art]
Electromagnetic vibrators such as audio speakers and vibration testing machines have a magnetic field line of a fixed magnetic field arranged so that the coil is supported by the suspension so that the direction of the current is orthogonal, and current flows through the coil. Within the range, the speaker cone connected to the coil and the sample stage are moved together with the coil. In the case of an audio amplifier and a speaker, the output (voltage), that is, the speaker input with respect to the amplifier input is designed to have low distortion by a feedback loop. In an audio system, sound is converted into a voltage by a microphone and immediately inputted to an amplifier and a speaker. Alternatively, it is input to the amplifier speaker through various recording media. When thinking of an ideal audio system, the sound of the sound source is input to the microphone and the output waveform is output, and the output of the microphone output is input to the amplifier and the speaker is driven to output sound and the sound is input to another microphone. As long as the waveform is the same, no such ideal audio system has yet emerged.
[0003]
The purpose of using the vibration tester is to apply vibration acceleration to the sample and test the resonance point and durability of the sample. The vibration acceleration waveform includes 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, in order to suppress the effect of resonance frequency by ignoring the phase shift, adjust the input signal while monitoring the average value, effective value, peak value, etc., and bring the output acceleration closer to the target value. Yes. Also, in the case of random excitation, check the correlation between the input spectrum waveform and the output spectrum waveform, design the filter so that the random input waveform will be the same as the original input waveform spectrum, and input the signal waveform through the filter Thus, a method is generally used in which the output waveform spectrum approaches the input waveform spectrum.
[0004]
[Problems to be solved by the invention]
In both vibration testing machines and audio speakers, the driving force is generated in common with the magnetic field and the current that flows through the coil. If the strength of the magnetic field is constant, the magnitude of the driving force is proportional to the strength of the current flowing through the coil. The coil and sample stage of the vibration tester, the voice coil and speaker cone of the speaker both have a finite mass, and the distortion of the driving force caused by the suspension restoring force due to displacement and the stiffness of the speaker cone, ie, the displacement distortion and magnetic field The input impedance of the coil changes greatly by moving in the.
[0005]
Also, speed loss such as internal loss resistance due to suspension deformation, loss due to frictional resistance, and internal loss due to deformation of the speaker cone occurs.
The relationship between the driving force (F), acceleration (α: acceleration), and mass (M: mass) is a state of free motion (Free Run) with no friction or resistance and no change in angular momentum.
F = Mα
When oscillating, it is an unequal accelerating motion, so if α is expressed as α = φ (t) where time is t, the velocity (V: Velocity) is
V = ∫φ (t) dt + V ₀
It is represented by
[0006]
The initial speed V ₀ may be set to V ₀ = 0 by the restoring force of the support device. This means that the velocity is linearly integrated with respect to the time of acceleration α.
About displacement (D: Displacement)
D = F (V) = ∫f (V) dV = ∫f {φ (t)} φ ′ (t) dt
For time t, this means that the acceleration has been quadratic integrated. 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 nothing to prevent vibration, and there is no influence on the motion of the vibrating body, that is, if it is free-running (FreeRun). For a vibrator, it is easy to obtain an acceleration α proportional to the input.
[0007]
Also, 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. Moreover, since elements 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 resonance frequency and real-time drive control impossible. In other words, it is the cause that “output proportional to input cannot be obtained”.
[0008]
As a countermeasure against this problem, a method of compensating for distortion, loss, and impedance change in the drive system itself composed of a speaker, a vibration exciter, and an amplifier can be considered to make the state close to free motion. In practice, this system becomes unstable as it approaches a state closer to free movement and tends to cause a runaway such as hunting.
What should be done in a stable and close to free motion state? If we consider again what it means to create and control a feedback loop here, if the dimensions are the same, the output is fed back to the input, that is, the input becomes the reference for the output.
[0009]
However, what should be the reference if the output cannot be based on the input if the dimensions are different? If direct input cannot be used as a reference, it is sufficient to perform the necessary calculations for the input, create samples of the same dimension, regard them as inputs of the same dimension, and compensate the output based on that.
In other words, in the case of a vibration tester or audio speaker, simulation of free motion in a form close to the theoretical value, predicting loss and distortion accompanying speed and displacement in advance, and performing appropriate compensation and correction in a timely manner will result in the simulation circuit. Stable and accurate correction and compensation can be achieved without introducing uncertain elements such as drive system drift.
The present invention aims to solve the above problems.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a control method for generating a vibration force in a coil by causing a vibration current to flow through the coil of an electromagnetic vibrator arranged so as to be orthogonal to a magnetic field line of a fixed magnetic field. In order to make the vibration of the electromagnetic vibration body proportional to the input signal as accurately as possible, a simulation circuit that outputs a signal close to the free motion of the vibration body with respect to the input signal is installed independently of the actual drive circuit. The circuit acceleration, speed, and displacement output signals are used to compensate for and correct distortion due to the mass, friction, and spring force of the vibrating body. The compensation-corrected signal is current amplified and supplied to the coil of the vibrating body. The input signal is vibrated in real time in proportion to the input signal.
[0011]
The present invention also relates to an electromagnetic vibrator control device for generating a vibration force in a coil by causing a vibration current to flow through the coil of the electromagnetic vibrator arranged 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 movement with respect to an input signal for vibrating the coil, and the mass, friction, and spring force of the vibrating body with respect to the output signal of the simulation circuit Compensation / correction calculation and level conversion circuit that compensates for loss distortion of the output and outputs a vibrator drive signal, and current that is amplified in the coil of the electromagnetic vibrator by amplifying the output signal of the compensation / correction calculation and level conversion circuit And a current amplification / current output circuit that vibrates and drives the coil.
[0012]
In the present invention, 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 performs linear integration of the acceleration signal with respect to time, and extracts the acceleration signal as a time signal. And a displacement signal generating circuit for quadratic integration and extracting as a displacement signal.
Further, according to the present invention, the compensation / correction calculation level conversion circuit has a first volume resistance set to a value corresponding to the mass of the vibrating body and a value corresponding to a friction force acting on the vibrating body. 2 and a third volume resistor set to a value corresponding to the spring force acting on the vibrating body, the acceleration output signal of the simulation circuit is compensated by the first volume resistor, and the simulation circuit The velocity output signal is compensated by the second volume resistance, and the displacement output signal of the simulation circuit is compensated by the third volume resistance.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
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 an audio signal or a vibration signal is input to the 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, velocity signal, and displacement signal indicate the free movement of the vibrating body with respect to the input. The output of the simulation circuit 2 is input to the compensation / correction calculation and level conversion circuit 4, where the mass of the vibrating body is compensated for the acceleration signal, and the friction loss of the vibrating body is compensated for the speed signal. The distortion signal is corrected for the distortion by the restoring force acting toward the neutral point due to the displacement of the vibrating body, that is, for the distortion by the spring force.
[0014]
Further, the compensation / correction signals of the respective signals are added and then subjected to level conversion and input to the subsequent current amplification / current output circuit 6. 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.
An input signal input from the input terminal T1 of the simulation circuit 2 is output as an acceleration signal to the ACC output line via the operational amplifier A1. The operational amplifier A1 changes the output impedance, and its output side is connected to an integrating circuit comprising a volume resistor VR1, resistors R1 and R2, and a capacitor C1.
[0015]
The input signal input from the input terminal T1 is supplied as an acceleration signal to the integrating circuit via the operational amplifier A1, integrated there, and converted in polarity by the operational amplifier A3, and output as a speed signal to the VEL output line. The speed signal is supplied to an integrating circuit composed of a volume resistor VR2, a resistor R3, and a capacitor C2, integrated there, and converted in polarity by the operational amplifier A5, and output as a displacement signal to the DISP output line. The acceleration signal, the velocity signal, and the displacement signal that are output to the output lines ACC, VEL, and DISP of the simulation circuit 2 correspond to the free movement of the vibration body of the audio speaker 8 or the vibration tester 10.
[0016]
Next, the compensation / correction calculation 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 the volume resistor VR4, and the displacement signal DISP is supplied to the volume resistor VR5. The volume resistance VR3 is set to a value corresponding to the mass of the vibrating body that prevents the free vibration of the vibrating body, and the loss due to the mass of the vibrating body is compensated for by the volume resistance VR3. The volume resistance VR4 is set to a value corresponding to the frictional force acting on the vibrating body that hinders the free movement of the vibrating body, and the volume resistance VR4 compensates for the loss of the speed movement of the vibrating body due to the frictional force of the vibrating body. .
[0017]
The volume resistance VR5 is set to a value corresponding to the spring force acting on the vibrating body, and the distortion due to the spring force of the displacement motion of the vibrating body is corrected by the volume resistance VR5. The acceleration, speed, and displacement signals compensated and corrected for loss, distortion due to mass, friction, and spring force are supplied to the operational amplifier A6, where they are added. The output of the operational amplifier A6 is sent to a level conversion circuit comprising operational amplifiers A7, A8, A9, A10, A11, and A12, where the compensation / correction calculation output of the operational amplifier A6 matches the current amplification / current output circuit 6 in the subsequent stage. Thus, the signal level is converted. The output signal of the compensation / correction calculation and level conversion circuit 4 is output to the current amplification / current output circuit 6, where the output signal is subjected to current amplification, and the current output is supplied to the load 8 or 10. Alternatively, the electromagnetic vibrator 10 is driven.
[0018]
【The invention's effect】
Since the present invention is configured as described above, the electromagnetic vibrator 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 compensation / correction calculation and level conversion circuit diagram.
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 (3)

In a control method for generating a vibration force in a coil by passing a vibration current through the coil of the electromagnetic vibration body arranged to be orthogonal to the magnetic field lines of the fixed magnetic field, the vibration of the electromagnetic vibration body is input. In order to make it proportional to the 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 circuit's acceleration, speed, and displacement output signals Is used to compensate and correct distortion due to the mass, friction, and spring force of the vibrating body, and this compensation-corrected signal is amplified by current and supplied to the coil of the vibrating body. so as to vibrate precisely in proportion, the simulation circuit includes an acceleration signal Concrete detection circuit for taking out a change in the input signal as an acceleration signal, the acceleration signal time Real-time control of the electromagnetic vibrator, characterized in that it comprises a speed signal forming detection circuit for taking out a primary integrated velocity signal, and a displacement signal Concrete detection circuit for taking out a secondary integrated displacement signal with respect to the acceleration signal time regarding Method. In an electromagnetic vibrator control device for generating a vibration force in a coil by passing a vibration current through the coil of the electromagnetic vibrator arranged so as to be orthogonal to the magnetic field lines of the fixed magnetic field, to vibrate the coil A simulation circuit that outputs acceleration, velocity, and displacement signals corresponding to free motion with respect to the input signal, and compensation and correction of loss distortion of mass, friction, and spring force of the vibrating body with respect to the output signal of the simulation circuit And a compensation / correction calculation and level conversion circuit for outputting a vibration body drive signal, and an output current of the compensation / correction calculation and level conversion circuit is current-amplified and the amplified current is supplied to the coil of the electromagnetic vibration body. the a current amplification-current output circuit for oscillatory drive, said simulation circuit includes an acceleration signal Concrete detection circuit for taking out a change in the input signal as an acceleration signal, the acceleration A velocity signal forming detection circuit for taking out a signal as the primary integrating the speed signal with respect to time, of the electromagnetic vibrator, characterized in that a displacement signal Concrete detection circuit for taking out a secondary integrated displacement signal with respect to the acceleration signal time Real-time control device. In an electromagnetic vibrator control device for generating a vibration force in a coil by passing a vibration current through the coil of the electromagnetic vibrator arranged so as to be orthogonal to the magnetic field lines of the fixed magnetic field, to vibrate the coil A simulation circuit that outputs acceleration, velocity, and displacement signals corresponding to free motion with respect to the input signal, and compensation and correction of loss distortion of mass, friction, and spring force of the vibrating body with respect to the output signal of the simulation circuit And a compensation / correction calculation and level conversion circuit for outputting a vibration body drive signal, and an output current of the compensation / correction calculation and level conversion circuit is current-amplified and the amplified current is supplied to the coil of the electromagnetic vibration body. the a current amplification-current output circuit for oscillatory drive, the compensation and correction operation level conversion circuit includes a first volume resistivity and which is set to a value corresponding to the mass of the vibrator An acceleration output of the simulation circuit, comprising: 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. The signal is compensated by the first volume resistance, the speed output signal of the simulation circuit is compensated by the second volume resistance, and the displacement output signal of the simulation circuit is corrected by the third volume resistance. A real-time control device for an electromagnetic vibrator characterized by that.

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