JPS63106019A - Active vibrationproof control method - Google Patents

Abstract

PURPOSE:To improve the vibrationproofing effect of a vibration component at a resonant frequency band area in a vibration system, by driving an actuator based on a signal obtained by adding arithmetic calculation including first order integration regarding the time of the output signal of a load detector. CONSTITUTION:It is possible to remarkably reduce a resonant response magnification by driving a piezoelectric actuator in proportion to the signal obtained by performing the first order integration on the output signal of the load detector. Therefore, a voltage signal V corresponding to the optimum increase quantity of the piezoelectric actuator 4 which lowers the resonant response magnification of the vibration system, can be found by a prescribed arithmetic processing, and the voltage signal V is amplified to the impression voltage Va of the piezoelectric actuator 4 by an amplifier 7. When the voltage Va is impressed on the piezoelectric actuator 4, and if a vibromotive force functions at a cycle in the neighborhood of the resonant frequency, the piezoelectric actuator is extended with the phase difference of 180 deg. against the vibromotive force, thereby, the vibration itself of a vibration source is suppressed, and the propagation of the force to a supporting table is suppressed, then, the vibration of the supporting table can be suppressed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an active vibration isolation control method, and more specifically, by improving the vibration isolation effect of vibration components in the resonant frequency band of a vibration system, The present invention relates to an active vibration damping control method that can suppress the value of the alternating force propagating through a vibration damping support device to a certain value or less regardless of the vibration source having any frequency.

[Conventional technology and its problems]

Mechanical vibrations of structural members are caused by propagation of vibrations from an excitation source. For this reason, suppressing the propagation of vibrations from the vibration sources has a great effect on damping the vibrations of structural members. A passive method of inserting anti-vibration rubber into the supporting end of the source has commonly been used. Although anti-vibration rubber has a suppressing effect over a wide frequency band, it is known that the suppressing effect is insufficient for the propagation of periodic and large vibrations. has become possible to think about.

This is a method that actively attempts to cancel vibrations based on signals obtained from the vibration source. The first is a method of vibration isolation by balancing forces, which involves applying a force in the opposite direction to the alternating force from the vibration source on the supporting end side, which is the object to be vibration-isolated. .

This method has the disadvantage that the device becomes bulky when the excitation force is large. The second method is to control the vibration of the vibration-isolated object by controlling the spring constant and changing the vibration system itself. This method also requires larger equipment.

The control is also complicated and it is disadvantageous in terms of cost.

Therefore, in order to solve the above-mentioned problems, the present inventor developed a vibration isolation system that suppresses the propagation of vibration to the vibration-isolated object by controlling the amount of extension of the piezoelectric actuator according to the mechanical vibration of the vibration source. He invented a control method and proposed it first.

The outline of this method is as shown in FIG.
The vibration isolating support device 3 is composed of a piezoelectric actuator 4 (displacement generating part), a load detector 5 and a vibration isolating rubber 12 arranged on the same axis as the piezoelectric actuator 4, Furthermore, an acceleration detector 11 is provided to detect the acceleration of the vibration source 1, and the variable load and acceleration when the vibration source 1 vibrates is measured, and the amount of elongation of the piezoelectric actuator 4 is determined based on the measured values. After calculating and converting this elongation amount into voltage, it is applied to the piezoelectric actuator 4 to suppress the propagation of vibration to the vibration-isolated object. , an adder 23 that adds the load signal Vf detected by the load detector 5 and the acceleration signal Vc detected by the acceleration detector 11, a second-order integrator 24, and a bias voltage required by the piezoelectric actuator for its output voltage. Adder 2 adds
The control system consists of 1. Note that 7 is an amplification section, ■ is a voltage signal, and Va is an applied voltage.

Ideally, this anti-vibration control method attempts to reduce the alternating force propagating through the anti-vibration support device to zero over the entire frequency band. However, when actually configuring the device, the alternating force propagating through the vibration isolating support device is not strictly O due to errors included in the signal detector, control system, amplifier, etc. The alternating force decreases at the same rate over the entire frequency band. For this reason,
Although the thickness of the alternating force becomes smaller overall, the resonance phenomenon of the vibration system remains, and the magnitude of the alternating force changes depending on the frequency of the excitation source. Therefore, in order to create a vibration isolating device that suppresses the value of the alternating force propagating through the vibration isolating support device to a certain level or less, regardless of the vibration source having any frequency,
The problem remains that the conventional control method described above is insufficient.

On the other hand, there are many cases in which a sufficient vibration isolation effect can be obtained simply by lowering the resonance response magnification.In such cases, it is sufficient to simply increase the damping effect, but conventionally, the output signal of an acceleration detector attached to a vibrating object The method used was to amplify the first-order integral and feed it back to the actuator. However, this requires the installation of a separate acceleration detector, which poses a problem of complicating the device.

The present invention has been made to solve the above problems,
The purpose is to improve the vibration damping effect of vibration components in the resonant frequency band of the vibration system, or furthermore, by combining it with the conventional active vibration damping control method, to prevent vibration sources with any frequency. An object of the present invention is to provide a vibration isolation control method that can suppress the value of alternating force propagating through a vibration support device to a certain value or less.

[Means for solving problems]

In order to achieve the above object, the active anti-vibration control method of the present invention provides an active anti-vibration control method in which in anti-vibration control using a support device consisting of an actuator and a load detector arranged in series, the output signal of the load detector has at least one order of magnitude in terms of time. The actuator is configured to drive the actuator based on a signal obtained by adding calculations including integration. Moreover, furthermore,
In combination with the conventional anti-vibration control method, the variable load and acceleration of the vibration source are measured, the amount of elongation of the actuator is calculated based on the measured values, and the amount of elongation is converted into voltage. When applying vibration to the actuator to perform anti-vibration control, the first-order integral of the variable load signal is further added to the control system including the second-order integral of the variable load and acceleration signals.

[Effect]

In this way, at least an actuator and a load detector are arranged in series, and the actuator is driven based on a signal obtained by first-order integration of the output signal of the load detector, so a vibration system can be created using a compact device. It becomes possible to greatly reduce the resonance response magnification of . Furthermore, since the spring is inserted in parallel to the actuator in a pre-tensioned state so that the actuator always acts in a compressive stress field, it will not break even if two laminated piezoelectric actuators are used as the actuator.

Furthermore, when combined with a conventional active vibration damping control method, a first-order integral of a variable load signal is added to the conventional control system including a second-order integral of a variable load and acceleration signal. therefore.

By controlling the voltage of the piezoelectric actuator incorporated in the vibration system of the vibration source according to the amplitude and frequency of the vibration, highly responsive and highly accurate vibration isolation control is performed. By adding the first-order integral of the signal, the vibration isolation effect for vibration components in the resonant frequency band of the vibration system is greatly improved, and vibration isolation support can be applied to vibration sources with any frequency. It becomes possible to suppress the value of the alternating force propagating through the device to a certain value or less.

〔Example〕

Three embodiments of the present invention will be described below with reference to the drawings. Note that FIG. 1 is a diagram of the vibration isolation control configuration for explaining the first embodiment of the active vibration isolation control method, FIG. 2 is a block diagram of the arithmetic unit of the present invention, and FIG. It is a figure showing an effect.

In FIG. 1, the vibration source 1 is the support base 2 on the side of the object to be vibration-isolated.
It is supported via an anti-vibration support device 3 attached to. Anti-vibration support device! ! 3 is a piezoelectric actuator 4 (displacement generating part) formed of a plurality of piezoelectric element disks made of piezoelectric ceramic such as zircon or lead titanate, and a load detector arranged on the same axis as the piezoelectric actuator 4. It consists of 5. The load detector 5 is constituted by a strain gauge, a piezoelectric load sensor, or the same piezoelectric element disk as the piezoelectric actuator 4.

The calculation unit 6 calculates the amount of elongation of the piezoelectric actuator 4 according to the fluctuating load of the vibration source detected by the load detector 5, and determines the amount of voltage control applied to the piezoelectric actuator 4 necessary to generate this amount of elongation. Calculate.

The amplification section 7 amplifies the output voltage from the calculation section 6 to the voltage applied to the piezoelectric actuator.

Next, the operation of the above embodiment will be explained.

When the vibration source 1 vibrates in the direction of arrow A in FIG. 1, a fluctuating load acts on the vibration isolation support device 3. This fluctuating load is detected by the load detector 5, and is output as a load signal Vf by the calculation unit 6.
is input.

Next, in order to show the calculation method according to the present invention, the vibration system shown in FIG. 1 will be described by the following equation of motion.

mz+c(z-u) +k(z-u) =P -(
1) Here, m is the mass of the vibration source 1, and C is the vibration-proof support bag! 2
! 3, k is the sum of the spring constants of the piezoelectric actuator 4 and the load detector 5, U is the amount of expansion and contraction of the piezoelectric actuator 4 and the expansion is positive, χ is the displacement of the excitation source 1 and upward is positive, P is the excitation force of the excitation source 1, and the upward direction is positive. Also, ( ) represents the second-order differential with respect to time, and (°) represents the first-order differential with respect to time.

The third term on the left side of equation (1) is equal to the force L (positive in the tensile example) detected by the load detector 5 in the support device.

In other words.

L=k (χ-U) ・・・・・・・・・・・・
- Since (2) is true, we can substitute equation (2) into equation (1) and eliminate χ. Therefore, the amount of expansion and contraction of the piezoelectric actuator is controlled, and an artificial viscosity coefficient C' is selected so that c+c'':'cc=2i, where c
c is the critical damping coefficient. If the amount of expansion and contraction of the piezoelectric actuator is controlled by U, which is obtained by substituting the value of C' into equation (4), the frequency characteristic of the alternating force propagating through the vibration isolator becomes the third It will look like the solid line in the figure.

In this figure, the dotted line is the characteristic when the piezoelectric actuator is not driven. From this result, if the piezoelectric actuator is driven in proportion to the signal obtained by first-order integration of the output signal of the cylindrical detection type as shown in equation (4).

It can be seen that it is possible to significantly reduce the resonance response magnification.

The control circuit shown in Figure 2 is an electric circuit based on equation (4).
Input the output voltage Vf of the load detector and calculate the integral of -20
After the voltage is passed through the adder 21, a bias voltage required by the piezoelectric actuator is added to the output voltage, and the voltage becomes a signal to the piezoelectric actuator. Here, A is determined by the following formula.

A=c'/mk2/(maT) Through the above calculation process, a voltage signal V corresponding to the optimal extension amount of the piezoelectric actuator 4 that reduces the resonance response magnification of the vibration system is obtained.This voltage signal V is The voltage Va applied to the piezoelectric actuator 4 is amplified by the amplifier 7 .

When voltage Va is applied to the piezoelectric actuator.

When an excitation force acts at a period near the resonance frequency, the piezoelectric actuator stretches with a phase difference of 180@ to the excitation force, suppressing the vibration of the excitation source itself, and as a result, the force on the support is reduced. propagation is suppressed, and vibration of the support base is prevented.

Next, a second embodiment in which a spring is inserted will be described with reference to the drawings. It should be noted that FIG. 4 is a configuration diagram of vibration isolation control for explaining an embodiment of an active vibration isolation control method, and FIG. 5 is a block diagram of a calculation section of the present invention.

In Fig. 4, the vibration source 1 and the support stand 2 on the side of the object to be vibration-isolated
are connected via threaded portions 8 and 9 of the vibration isolating support device 3. Anti-vibration support device! 3 consists of a piezoelectric actuator 4 (displacement generating section), a load detector 5 disposed on the same axis as the piezoelectric actuator 4, and a spring 1o disposed in parallel thereto. The spring 10 is initially set in tension to precompress the piezoelectric actuator.

The calculation unit 6 calculates the amount of elongation of the piezoelectric actuator 4 according to the fluctuating load of the vibration source detected by the load detector 5, and determines the amount of voltage control applied to the piezoelectric actuator 4 necessary to generate this amount of elongation. Calculate.

The amplifier 7 amplifies the output voltage from the arithmetic unit 6 to the voltage applied to the piezoelectric actuator.

Next, in order to show the calculation method in this embodiment, the vibration system shown in FIG. 4 will first be described using the following equation of motion, as in the first embodiment.

mz+c(z-u)+k(z-u)+k' χ=P
-+-...++-(6) Here, ' is the spring constant of the spring 10. The third term on the left side of equation (6) is equal to the force detected by the load detector 5 in the support device, as seen from equation (2).

Moreover, in this case, the support device i! The spring force F propagated through 3 is F==L+k'χ, so substituting the above equation and equation (2) into equation (6) to eliminate χ. Therefore, if the amount of expansion and contraction U of the piezoelectric actuator is controlled so that it satisfies mku-ck'u=c' F, then equation (7) will change equation (5) from L→
This is equivalent to the equation in which -4 is replaced by +k' for F, and the result is similar to that of the first embodiment.

The control circuit in Figure 5 is an electrical circuit of equation (8),
Multiply the output voltage Vf of the load detector by (k+')A/,
- is input to the integrator 20 of the -th floor. Then, it is fed back to the device 22. At this time, the voltage obtained by adding the bias voltage to the output signal of the integrator 20 by the adder 21 becomes a signal to the piezoelectric actuator.

Through the above calculation processing, as in the first embodiment, the vibration itself of the excitation source having a period near the resonance frequency is suppressed,
As a result, vibration of the support base is prevented.

Finally, a third embodiment that combines conventional vibration isolation control methods will be described with reference to the drawings. In addition, FIG. 6 is a vibration isolation control configuration diagram for explaining an embodiment of the active vibration isolation control method, FIG. 7 is a block diagram of a calculation section of the present invention, FIG. 10 is a block diagram of a conventional calculation section, and FIG. FIG. 8 is a comparison diagram of the frequency characteristics of the alternating force propagating through the vibration isolating support device.

In FIG. 6, the vibration source 1 is supported via a vibration isolation support device 3 attached to a support base 2 on the side of the object to be vibrated.

The vibration isolation support WL3 includes a piezoelectric actuator 4 (displacement generating section) and a load detector 5 arranged on the same axis as the piezoelectric actuator 4. Also, the acceleration of the excitation source! An acceleration detector 11 is provided for detection.

The calculation unit 6 calculates the amount of elongation of the piezoelectric actuator 4 according to the fluctuating load and acceleration of the excitation source detected by the load detector 5 and the acceleration detector 11, and determines the amount of elongation of the piezoelectric actuator 4 necessary to generate this amount of elongation. The applied voltage control amount to 4 is calculated.

The amplifier 7 applies the output voltage from the arithmetic unit 6 to the pressure vibration isolation support device 3, which is subjected to a variable load. This fluctuating load is detected by the load detector 5, and is output as a load signal Vf by the calculation unit 6.
is input. At the same time, the acceleration of the excitation source is detected by the acceleration detection section 11, and the acceleration signal Vc is detected by the calculation section 6.
is input.

Next, to show the difference between the arithmetic unit (FIG. 7) and the conventional one (FIG. 10) according to the present invention, which will be described later.

When the vibration system of FIG. 6 is described by an equation of motion, it is expressed by equation (3) as in the first embodiment. Therefore u = P
/ m ・・・・・・・・・・・・・・・
By controlling the expansion/contraction amount U of the piezoelectric actuator so as to satisfy (9), L=L=O (1
0), and the alternating force propagating through the vibration isolating support device becomes 0. The value of P on the right side of equation (9) is determined by using equation (1) and equation (2): P = mz + (c/k) L + L ---
0 The first term on the right side of equation (11), χ, which can be actually measured using (CH), is the acceleration signal Vc of the acceleration detector 11 attached to the excitation source; The load can be measured from the load signal Vf of the load detector 5 in the vibration isolating support device.

Therefore, the amount of expansion and contraction U of the piezoelectric actuator that satisfies Equation 1 (9) is u” fl (Z+(c/mk)L+(1/m)L)d
It can be determined from tdt - (12). The conventional calculation section shown in FIG. 10 is a calculation circuit when the damping coefficient C in equation (12) is ignored as being small. That is, in the arithmetic unit 6, both signals are first added by the adder 23. At this time, the load signal Vf is multiplied by a conversion coefficient B.
Specifically, B=Kc/(Kf-m), where Kf and Kc are the load-voltage conversion coefficient and acceleration-voltage conversion coefficient of the load detector and acceleration detector. Then, the output voltage of the adder 23 is input to the second-order integrator 24, and the voltage obtained by adding a bias voltage required by the piezoelectric actuator to the output voltage by the adder 21 becomes a signal to the piezoelectric actuator.

When the amount of expansion and contraction U of the piezoelectric actuator is controlled in this way, the alternating force that propagates through the vibration isolation support device ideally becomes O. However, in actual equipment, the amount of expansion and contraction is expressed by the formula (12
) will not completely match the value found from

π=(1-ε)U ・・・・・・・・・・・・・・・
...(13). Here, ε is a coefficient representing an error caused by the signal detector, control system, amplifier, etc. In this case, from equation (9) mu = (1-i) mu = (1-g) P ・
-(14), and equation (3) becomes as follows when i is used instead of U.

mL+cL+kL=ikP---(1
5) At this time, the frequency response of the alternating force propagating through the vibration isolating support device becomes as shown by the dashed-dotted line in FIG. This is shown by the dotted line when the piezoelectric actuator is not driven (ε-1
), the magnitude of the alternating force is overall reduced by a factor of ε.

However, even if the piezoelectric actuator is driven and active anti-vibration control is performed, a resonance phenomenon remains, so the magnitude of the alternating force propagating through the anti-vibration support device varies greatly depending on the frequency.

The ratio of the alternating force to the static load during resonance depends on the magnitude of the damping coefficient C of the vibration system. Therefore, selecting a vibration isolating support device with a large value has the effect of reducing the alternating force during resonance, but by using the control system, the value of this damping coefficient C can be electrically increased. is more effective. This can be achieved as follows.

If the amount of expansion and contraction of the piezoelectric actuator is controlled by instead of U in formula (12), the formula % formula %
), and formula (3) uses ul instead of U, then c+ (1-ε) c'= ac=2p
----Choose C' so that it becomes (20).

When this value of C' is used in equation (16), the frequency characteristic of the alternating force propagating through the vibration isolating support device becomes as shown by the solid line in FIG. In the calculation of equation (20), ε=0
・・・・・・・・・Even if (21), the error is small,
In the example shown in Figure 8, formula (21) is converted to % formula % In this way, by adding the term of the first-order integral of the output signal of the load detector to the conventional control method, the vibration isolation effect is greatly improved. do.

The control circuit shown in Fig. 7 is an electric circuit of equation 1 (16), in which a signal obtained by multiplying the load signal Vf of the load detector by 8 is further multiplied by 0, and then inputted to the integrator 20 on the - floor. The output is coupled to conventional control circuitry by an adder 25.

Here, C is determined from the following equation.

By the above calculation process, a voltage signal V corresponding to the optimum amount of extension of the piezoelectric actuator 4 that controls the propagation of vibration from the vibration source is determined by C=(c+c')/. This voltage signal V is amplified by the amplifier 7 to a voltage Va applied to the piezoelectric actuator 4.

When voltage Va is applied to the piezoelectric actuator.

The piezoelectric actuator extends in the displacement direction 1 of the vibration source, for example, upward in FIG. In addition, the vibration of an excitation source having a period close to the resonance frequency is itself suppressed. In this way, the propagation of force to the support base due to the vibration of the vibration source is suppressed, and vibration of the support base is prevented.

〔Effect of the invention〕

As described above, according to the present invention, a piezoelectric actuator is incorporated in the vibration system of the vibration source, and this piezoelectric actuator expands and contracts in accordance with the vibration of the vibration source to damp vibration, so that responsiveness is good. In addition to being able to perform highly accurate anti-vibration control, the present invention has a configuration in which at least an actuator and a load detector are arranged in series, and the actuator is driven based on a signal obtained by first-order integration of the output signal of the load detector. Therefore, the resonance response magnification of the vibration system can be greatly reduced with a compact device. Also.

By inserting a spring in parallel to the actuator so that the actuator always acts in a compressive stress field,
Even if a laminated piezoelectric actuator is used as an actuator, it will not break.

Furthermore, in combination with the conventional active vibration isolation control method, in addition to the second-order integral of the variable load and acceleration signals, the first-order integral of the variable load signal is added to the control system, which increases the resonance frequency of the vibration system. The vibration isolation effect for vibration components in the band has been greatly improved, and the value of the alternating force propagating through the vibration isolation support device can be suppressed to a certain level or less, regardless of the vibration source of any frequency. be able to.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the vibration isolation control configuration for explaining the first embodiment of the active anti-vibration control method, Fig. 2 is a block diagram of its calculation section, and Fig. 3 is a diagram showing the effects of the first embodiment. , FIG. 4 is a configuration diagram of vibration isolation control for explaining a second embodiment of the active vibration isolation control method, and FIG. 5 is a block diagram of its calculation unit.
Fig. 6 is a block diagram of vibration isolation control for explaining the third embodiment of the active vibration isolation control method, Fig. 7 is a block diagram of its calculation section, and Fig. 8 shows the effect of the third embodiment. 9 is a block diagram of a conventional active vibration damping control, and FIG. 10 is a block diagram of its calculation section. 1... Vibration source, 2... Support stand (vibration-isolated object)
, 3... Anti-vibration support device, 4... Piezoelectric actuator, 5... Load detector, 6... Calculation unit, 7...
- Amplifying section, 10... Spring, 11... Acceleration detection section -20... - floor integrator, 24... Second floor integrator.

Claims (3)

[Claims] (1) In vibration isolation control using a support device consisting of an actuator and a load detector arranged in series, the actuator is controlled based on a signal obtained by adding an operation including at least a first-order integral with respect to time to the output signal of the load detector. An active anti-vibration control method characterized by driving. (2) The active vibration damping control method according to claim 1, characterized in that a spring is inserted in parallel to the actuator. (3) Measure the fluctuating load and acceleration when the vibration source vibrates, calculate the amount of elongation of the actuator based on the measured values, convert the amount of elongation into voltage, and then apply it to the actuator to prevent vibrations. An active anti-vibration control method characterized in that, in performing control, a first-order integral of a variable load signal is further added to a control system including a second-order integral of the variable load and acceleration signals.