JP2013061042A - Vibration isolation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide vibration isolation equipment, which has stable vibration insulation ability even for microscopic vibrations from low frequency and has effective damping characteristics in high frequency band as compared to conventional hybrid type vibration isolation equipment.SOLUTION: The vibration isolation equipment includes: a first spring 102 disposed between a base and payload; a vibration absorption part which comprises a second spring 103 and damper 106, which are subjected to series connection between the base and payload while being provided together with the first spring, and a connection part 104 constituting an intermediate mass for connecting the second spring and damper; an actuator 101 which is disposed between the base and payload and suppresses vibrations of the payload for the base; a first motion sensor 107 mounted on the payload; a second motion sensor 105 mounted on the connection part of the vibration absorption part; and an actuator control system which includes a control part 120 for controlling the actuator to suppress the vibration of the payload in accordance with a feedback signal from the first and second motion sensors.

Description

  The present invention relates to the field of vibration damping and vibration isolation, and more particularly to a vibration isolation device (vibration isolation strut) including a passive viscous damping mechanism and an active actuator constituting the vibration isolation device. .

  When a precision instrument is transported or operated, structural vibration may occur inside the precision instrument. This structural vibration may cause damage to precision equipment and performance degradation. Therefore, in order to avoid this, in many cases, a vibration damping device is provided in order to insulate the disturbance to the precision instrument, and the generation of vibration inside the precision instrument is suppressed.

  In order to solve these problems, various vibration isolation devices have been developed by passive and active methods. In the case of the passive system, a three-parameter vibration isolation strut mechanically composed of a viscous damping damper, a second spring arranged in series with the damper, and a first spring arranged in parallel with the damper and the second spring. It is known that it is composed of a plurality of pieces. In addition to the three-parameter vibration isolation struts, the vibration isolation performance is slightly reduced. However, the two parameters of the spring and viscous damping damper are arranged in parallel, and the fluid inertia mass (intermediate mass) of the damper is taken into consideration for the three parameters. A method using a four-parameter vibration isolation strut is also known.

  On the other hand, this vibration isolation strut configuration includes an active type in which an actuator such as a voice coil or a piezoelectric element is combined with an acceleration sensor, and the output of the acceleration sensor is fed back to control the actuator.

  Furthermore, a hybrid type vibration isolation strut combining the passive method and the active method is also known.

  A general vibration isolator has a plurality of degrees of freedom by connecting one end of the above-mentioned vibration isolation struts to the platform side (base) on which precision instruments are mounted, and the other end to a precision equipment mounting deck (payload). Against vibration transmission. These vibration insulation characteristics are generally evaluated by a vibration transfer function. In the case of a passive system composed of a viscous damping damper and a spring, in the case of three parameters, attenuation of -40 dB / decade, which has a higher damping effect than that in the case of four parameters, can be realized at -60 dB / decade. Because it becomes possible, it is better to apply a high-damping precision instrument to a precision instrument that is more sensitive to vibration. However, in the case of this passive method, it has a vibration isolation effect in the high frequency band, but in principle it always has resonance at a lower frequency, and it can be vibration isolated in a wide band from low frequency to high frequency. difficult.

  In the case of the active method, an actuator and a sensor such as an acceleration sensor are used. Although the vibration isolation performance can be suppressed from a low frequency, the actuator control band and the sampling frequency of the sensor such as an acceleration sensor are used for the high frequency band. It will be restricted by the bandwidth. In addition, when a failure occurs, there is a problem in that it falls into a malfunction. A hybrid system vibration isolation strut is a system that covers the disadvantages of the passive system and the active system. As for this characteristic, vibration isolation can be realized by the active method for the low frequency band, and vibration isolation performance can be achieved for the high frequency from the low frequency to the high frequency because it can have the vibration isolation performance of the passive method. It has features that make it possible.

  For example, the following Patent Document 1 discloses the passive vibration isolation strut, and the following Patent Document 2 discloses the hybrid vibration isolation strut.

Special table 2007-531852 gazette JP 2008-254726 A

  In this way, in the vibration isolator (vibration isolation strut), there are three methods for isolating vibration: a hybrid method combining the passive method and the active method, when realizing only with the passive method and when realizing only with the active method. There is.

  As described above, in the case of the passive method, as a method of increasing the damping performance, mechanically, the viscous damping damper, the second spring arranged in series with the damper, and the damper and the second spring are arranged in parallel. Three parameters composed of the first spring are known, and in this case, it is known that the damping characteristic has a characteristic of −40 dB / dec (see the damping characteristic 403 in FIG. 8). Furthermore, as a method of improving this characteristic, the damping characteristic is reduced at −60 dB / dec by considering an intermediate mass constituted by the fluid mass inside the oil damper constituted by the three-parameter vibration insulation strut and the mass of the coupling member. This can be realized (see the attenuation characteristic 404 in FIG. 8). However, in order to realize this characteristic, it is necessary to adjust the intermediate mass with high accuracy, and there is a problem that the characteristic cannot be obtained unless it is appropriately adjusted. In addition, since it always has a resonance point, there is also a problem that an attenuation effect can be obtained only in a region where the transfer function is lower than 0 dB at a frequency higher than the resonance frequency.

  In the case of the active method, which is the second method, if the active actuator fails, the vibration insulation effect cannot be obtained at all. For example, when mounted on a spacecraft, the observation accuracy deteriorates due to vibration from the satellite body, etc. There was a problem of increasing the risk.

  Furthermore, as a third method for solving these problems, a hybrid method combining a passive method and an active method has been developed. The hybrid type passive type part uses the above-mentioned three-parameter type, and the active type part uses a voice coil, an actuator such as a piezoelectric element, and an inertial sensor such as an acceleration sensor, thereby isolating vibration in a low frequency band. The band that can secure the effect and cannot be controlled by the active actuator can be vibration-isolated using the passive method of the three-parameter damper (see the damping characteristic 402 in FIG. 8). However, in the case of this method, since the passive vibration isolation strut of the passive method is used, there is a problem that only a damping characteristic at −40 dB / dec can be secured at a high frequency. Further, in order to achieve a more effective vibration isolation effect at high frequencies, there has been a problem that when a four-parameter passive vibration strut is realized, it can be realized only by finely adjusting the fluid mass.

  The present invention has been made to solve the above-described problems, has stable vibration isolation capability even with minute vibrations from low frequencies, and is higher than the conventional hybrid vibration isolation device. An object of the present invention is to provide a vibration isolator having an effective attenuation characteristic in the frequency band (see the attenuation characteristic 401 in FIG. 8).

  According to the present invention, a first spring provided between a base and a payload, a second spring and a damper connected in series between the base and the payload in parallel with the first spring, and the second A vibration absorbing portion comprising a connecting portion constituting an intermediate mass for connecting between the spring and the damper, an actuator provided between the base and the payload for suppressing the vibration of the payload with respect to the base, and the payload In order to suppress vibration of the payload in accordance with feedback signals from the first motion sensor mounted, the second motion sensor mounted at the connection portion of the vibration absorber, and the first and second motion sensors. And an actuator control system including a control unit for controlling the actuator.

  According to the present invention, it is possible to provide a vibration isolator having a stable vibration isolation capability even with a minute vibration from a low frequency and having an effective damping characteristic in a higher frequency band as compared with a conventional hybrid vibration isolator.

It is a figure which shows the basic composition of the hybrid type vibration isolator by Embodiment 1 of this invention. It is sectional drawing which shows an example of the specific structure of the vibration isolation strut of FIG. It is a block diagram which shows the basic composition of the actuator control system in control by the control part of the vibration isolation strut of FIG. It is a block diagram which shows the basic composition of the actuator control system in control by the control part of the vibration isolation strut in Embodiment 3 of this invention. It is a figure which shows the basic composition of the hybrid type vibration isolator in Embodiment 6 of this invention. It is a block diagram which shows the basic composition of the actuator control system in control by the control part of the vibration isolation strut in Embodiment 6 of this invention. It is a block diagram which shows the basic composition of the actuator control system in control by the control part of the vibration isolation strut in Embodiment 7 of this invention. FIG. 6 is a diagram comparing vibration isolation (damping characteristics) of the present invention with vibration isolation characteristics according to the prior art.

  Hereinafter, a vibration isolator according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
FIG. 1 shows a basic configuration of a hybrid vibration isolator according to Embodiment 1 of the present invention. A second spring 103 and a damper 106 are arranged in series between a base surface (base) 109 and a payload mounting surface (payload) 108, and a connection for connecting them between the second spring 103 and the damper 106 An intermediate mass 104 corresponding to the mass of the portion is disposed, and a four-parameter vibration isolation strut portion 111 in which the first spring 102 is disposed in parallel to the second spring 103, the damper 106, and the intermediate mass 104 is provided. The active actuator 101 (for example, voice coil) is disposed in parallel. For example, an acceleration sensor 105, which is a motion sensor, is disposed on the intermediate mass 104, and similarly, an acceleration sensor 107 is disposed on the payload mounting surface. The above portions constitute the vibration isolation strut 1.

  A control unit 120 configured by a computer or the like controls the active actuator 101 in accordance with signals from the acceleration sensors 105 and 107.

  FIG. 2 is a cross-sectional view showing an example of a specific configuration of the vibration isolation strut 1. The vibration isolation strut 1 includes a shaft axis 201 having a central axis 200. The shaft shaft 201 connects the first end 202 to the base member 204 and the second end 203 to the end member 205. A first bellows 206 is connected to the base member 204, and a second bellows 207 is connected to the end member 205. The flange 208 is arranged coaxially with the shaft shaft 201. The flange 208 is larger in diameter than the shaft shaft 201, extends along the outer periphery of the shaft shaft 201, has a hole having a smaller diameter than the first and second bellows 206 and 207, and is annular between the flange 208 and the shaft shaft 201. A flow path 209 is formed. The fluid includes a volume chamber A210 formed by the first bellows 206 and the first end portion 202, a volume chamber B211 formed by the second bellows 207 and the second end portion 203, and these volumes. The annular flow path 209 connecting the chambers is filled, and a braking force as a damper is generated by moving back and forth along the annular flow path 209 with vibration.

  The outer side of the flange 208 is fixed to the inner side of one end of the cylindrical rigid member A216 in the axial direction, for example, and the other end of the rigid member A216 is sandwiched with the outer end of the first leaf spring A214. One end of the rigid member B217 in the axial direction is connected. The outer end of the second leaf spring B215 is fixed to the other end of the rigid member B217. The inner end of the first leaf spring A214 is connected to one end in the axial direction of, for example, a cylindrical rigid member C218 extending in the same direction inside the rigid member B217, and the inner end of the second leaf spring B215 is connected to the rigid member. It is fixed in such a manner as to be sandwiched between the other end of C218 and one end in the axial direction of, for example, a cylindrical rigid member D219. Accordingly, the first plate spring A214 and the second plate spring B215 ensure springiness between the rigid member A216 and the rigid member B217, and the rigid member C218 and the rigid member D219.

  On the other hand, the third leaf spring C212 is fixed in such a manner that the outer end is sandwiched between the cover A222 and one end of the cylindrical rigid member E220 in the axial direction, for example. The inner end of the third leaf spring C212 is connected to one end in the axial direction of, for example, a cylindrical rigid member F221. Similarly, the fourth plate spring D213 has an outer end fixed to the other end of a cylindrical rigid member E220, for example, and an inner end fixed so as to be sandwiched between the rigid member F221 and the cover B223. Accordingly, the third leaf spring C212 and the fourth leaf spring D213 ensure springiness between the cover A222 and the rigid member E220, and the rigid member F221 and the cover B223.

  A pivot A224 is connected to the cover A222 to form a strut end A226. Similarly, a biaxial pivot B225 is connected to the cover B223 to form a strut end B227. Further, the acceleration sensor 105 mounted on the intermediate mass 104 shown in FIG. 1 is disposed in the rigid member A216, and the acceleration sensor 107 mounted on the payload mounting surface 108 is disposed in the cover A222. The sensor sensitivity axis is parallel to the central axis 200 shown in FIG. Further, the active actuator 101 includes a voice coil that is a non-contact actuator including a magnet 231 disposed on the rigid member E220 and a coil 232 disposed on the rigid member F221 shown in FIG. The intermediate mass 104 means a mass composed of the flange 208 and the rigid member A216 (which may further include fluid filled in the first and second bellows 206, 207).

  The strut end B227 of FIG. 2 is connected to the base surface 109 of FIG. The strut end A226 is connected to the payload mounting surface 108. The third plate spring C212 and the fourth plate spring D213 constitute the first spring 102, and the third plate spring C212 and the fourth plate spring D213 constitute the second spring 103. The shaft shaft 201, the end member 205, the first and second bellows 206 and 207, and the fluid filled in the first and second bellows 206 and 207 constitute the damper 106. Further, the flange 208 and the rigid member A 216 (which may further include fluid filled in the first and second bellows 206 and 207) constitute the intermediate mass 104. The magnet 231 and the coil 232 constitute the active actuator 101.

  In addition, the second spring 103 and the damper 106 connected in series in FIG. 1 and the intermediate mass 104 (the flange 208, the rigid member A216, (and the first and second bellows 206) which are connecting portions connecting them are connected. , 207 may be included))) constitutes the vibration absorbing portion.

  FIG. 3 is a block diagram showing a basic configuration of an actuator control system controlled by the control unit 120 of the vibration isolation strut 1 of FIG. This control system is a cascade connection of a current control system and an acceleration control system. In FIG. 3, the actuator control system includes calculation units 10, 14, and 19, an addition unit 13, subtraction units 11, 15, and 20, acceleration controllers 12, 21 that perform predetermined calculations and generate predetermined outputs, current control, and the like. 16 and acceleration sensors 107 and 105. Then, control is performed to apply a voltage to the voice coil 101 in accordance with vibration that cannot be suppressed from the vibration isolator 18 corresponding to the four-parameter vibration isolation strut portion 111.

The acceleration control means including the calculation unit 10, the subtraction unit 11, the acceleration controller 12, the addition unit 13, the calculation unit 19, the subtraction unit 20, and the acceleration controller 21 is based on the feedback signal of the motion sensor (107, 105). The voice coil (active actuator) is obtained by performing PI control or P control with the acceleration controller (12, 21) so that the acceleration of the payload mounting surface 108 and the intermediate mass (connection portion of the vibration absorbing unit) 104 obtained by the above are respectively zero. ) The force command value (F ^* ) to 101 is obtained. Further, the current control means including the calculation unit 14, the subtraction unit 15, and the current controller 16 converts the force command value (F ^* ) into the current command value (I ^* ), and then determines the current according to the characteristics of the voice coil. The controller (16) generates an applied voltage (V _in ) to the voice coil.

The current control system is a current feedback 33, while the acceleration control system is composed of an acceleration feedback 32 on the payload mounting surface 108 and an acceleration feedback 31 on the intermediate mass 104. The acceleration controllers 12 and 21 together constitute a PI control system or a P control system. Further, outputs from the acceleration controllers 12 and 21 become a force command value F ^* to the voice coil 101.

The control system measures the output (Tsudotto) X _F Output (Tsudotto) X _p and the acceleration sensor 105 mounted on the intermediate mass 104 of the acceleration sensor 107 mounted in the payload mounting surface 108 of the vibration isolation strut 1 Control is performed by applying a voltage to the coil 232 of the voice coil 101 which is an active actuator in the vibration isolation strut 1 so that the outputs of the acceleration sensors 107 and 105 are zero.

  The equation of motion of the configuration of the vibration isolation strut 1 shown in FIG. 1 can be described as follows.

Where m _p : mass to support including payload mounting surface 108 m _F : mass of intermediate mass 104 k ₁ : rigidity of first spring 102 k ₂ : rigidity of second spring 103 c: damping coefficient of damper 106 X _p : position displacement of payload mass m _p X _F : position displacement of intermediate mass m _F X _B : position displacement of base surface 109
(Dot) X _p : speed of payload mass m _p
(Dot) X _F : Intermediate mass m _F speed F: Force generated by voice coil 101 (actuator)
It is.

As for the configuration of the control system, as an acceleration control system, acceleration signals (two dots) X _{p and} (two dots) X _F of the acceleration sensor 105 disposed on the intermediate mass 104 and the acceleration sensor 107 disposed on the payload mounting surface 108 are used. It is necessary to control the voice coil 101 so that both become zero. The force command F ^* to the voice coil 101 is obtained when both the acceleration sensor 107 on the payload mounting surface 108 and the acceleration sensor 105 disposed on the intermediate mass 104 are combined with PI control (control in which proportional action and integral action are combined). If the proportional gain α and integral gain β of PI control of the acceleration controller 12 are set, and the proportional gain γ and integral gain μ are set by PI control of the acceleration controller 21, the following expression (3) can be given.

  Using this as the Laplace operator s and Laplace transform,

And can be transformed.

  On the other hand, when actually designing the control system, it is necessary to consider the characteristics of the voice coil 101. The characteristic equation of the voice coil is

Indicated by here,
I (t): excitation current of the voice coil 101 K _T : thrust constant of the voice coil 101 L: inductance of the voice coil 101 R: winding resistance of the voice coil 101 K _E : induced electromotive force constant of the voice coil 101 (= K _T )
V _in : voltage applied to the voice coil 101
(Dot) _XP : Payload surface speed
(Dot) X _B : The speed of the base surface.

In addition, the PI control system is used as the current control system, and the proportional gain K _p (current) and the integral gain K _I (current) are defined.
K _p (current) = K _Pe
K _{I (current) = (R / L) K} Pe
Then, the open loop transfer function G (current) of the current control system is
G (current) = K _Pe / (L · s)
The gain crossover angular frequency ω _e of the current control system is
ω _e (current) = K _Pe / L
It becomes.

On the other hand, the closed loop transfer function of the current control system is G (current) = ω _e / (s + ω _e )
Therefore, the generated force F (s) of the voice coil considering the closed-loop transmission characteristics of current control is

It becomes. I ^* (s) shown in FIG. 3 is obtained by converting the voice command force command value F ^* (s) output from the acceleration controllers 12 and 25 into a current command value.
The transfer function of the displacement X _P payload mounting surface 108 with respect to the displacement X _B of the base surface 109 of the acceleration (Tsudotto) system includes a feedback control of the X _F of the intermediate mass 104, and simultaneous equation (1) to (3) In particular, it can be described as follows.

  As described above, a first-order delay due to the closed-loop transfer characteristic of the current control system is included, and the denominator is a fifth-order transfer function with respect to the second-order characteristic of the numerator. At this time, the proportional gain γ and the integral gain μ of the acceleration controller 25 of the intermediate mass 104 are respectively

And by setting the molecular transfer function G (s) of the payload displacement X _P relative to the base displacement X _B

Thus, in (m _f · ω ³ << k ₂ · ω _e ), the numerator order is 0th order and the denominator order is 4th order, and it is possible to realize an attenuation characteristic of −80 dB / dec at a high frequency. According to this configuration, the damping characteristic of the frequency satisfying the condition of (m _f · ω ³ << k ₂ · ω _e ) of the hybrid type vibration isolation strut 1 is the passive type (three parameters) that is responsible for the characteristic. A damping characteristic of -80 dB / dec can be realized with respect to the vibration isolation performance of -40 dB / dec, and resonance generated by the intermediate mass 104 and the first spring 102 as a secondary spring is also suppressed. It becomes possible.

Embodiment 2. FIG.
The basic configuration of the vibration isolator according to Embodiment 2 of the present invention and the basic configuration of the actuator control system in the control by the control unit of the vibration isolation strut are the same as those in FIGS. In the first embodiment, the intermediate mass 104 is a connecting member (the flange 208 and the rigid member A 216 in FIG. 2) between the second spring 103 and the damper 106. However, the intermediate mass 104 includes the damper 106, that is, the damper 106 in FIG. A configuration including the fluid mass of the fluid filled in the bellows 206, 207 may be employed. By considering the fluid mass in the intermediate mass 104, the intermediate mass can be accurately controlled, and the vibration isolation performance can be improved.

Embodiment 3 FIG.
The basic configuration of the vibration isolator according to Embodiment 3 of the present invention is substantially the same as that shown in FIG. 1, but FIG. 4 shows the basic configuration of the actuator control system in the control by the control unit of the vibration isolation strut. In the above embodiment, the acceleration sensors 105 and 107 are mounted as sensors for monitoring the movement of the intermediate mass 104 and the movement of the payload mounting surface 108 for the acceleration feedbacks 31 and 32 to the acceleration control system. Instead of the sensor 105, a relative displacement sensor 105a composed of, for example, an eddy current displacement sensor capable of measuring the relative displacement between the payload mounting surface 108 and the intermediate mass 104 may be mounted inside the strut (the same applies to FIG. 1). This relative displacement sensor may be disposed, for example, in any one of the rigid member A216 and the end member 205 in FIG.

As for the basic configuration of the actuator control system in that case, as shown in FIG. 4, X _F -X _P which is the output 34 of the relative displacement sensor 105a is taken into the differentiator 26, and the relative acceleration is obtained. And obtaining the absolute acceleration (Tsudotto) X _F summing the acceleration (Tsudotto) X _P from the acceleration sensor 107 of the payload mounting surface 108 on said relative acceleration adder 25.

  According to this configuration, in the case of a very compact passive vibration isolation strut 111, an acceleration sensor cannot be mounted on a component forming the intermediate mass 104, but an eddy current displacement sensor is provided. Thus, the displacement can be monitored, and a compact hybrid vibration isolation strut 1 can be configured.

Embodiment 4 FIG.
The basic configuration of the vibration isolator according to Embodiment 4 of the present invention and the basic configuration of the actuator control system in the control by the control unit of the vibration isolation strut are the same as those of the above embodiment. In the above embodiment, a fluid damper is used as the damper 106. However, as long as the damper 106 has an effect of a damper, an electric magnetic damper, a viscoelastic damper using a viscoelastic body, or the like is used. Also good.

  If it is this structure, the characteristic similar to the case where a fluid damper is used is securable. In the case of a fluid damper, the temperature dependency is high, and the viscosity changes depending on the temperature. For this reason, depending on the temperature range, it may differ greatly from the design value, and the desired attenuation characteristic may not be realized. In particular, when a magnetic damper is used, unnecessary friction does not occur because there is no mechanical contact like a fluid damper, and the damping coefficient does not change due to temperature unlike a fluid damper. It is possible to provide resistance to the attenuation characteristics.

Embodiment 5 FIG.
The basic configuration of the vibration isolator according to Embodiment 5 of the present invention and the basic configuration of the actuator control system in the control by the control unit of the vibration isolation strut are the same as those of the above embodiment. In the above embodiment, for example, in FIG. 3, the acceleration controller 12 using the output of the acceleration sensor 107 on the payload mounting surface 108 is configured to use PI control, but the acceleration controller 12 may be configured to use P control. Good. Similarly, although the acceleration controller 21 that uses the acceleration sensor output of the acceleration sensor 105 mounted on the intermediate mass 104 uses PI control, the acceleration controller 21 may be configured to use P control.

  According to this configuration, the electrical circuit of the acceleration controllers 12 and 21 can be simplified compared to the PI controller.

Embodiment 6 FIG.
FIG. 5 shows a basic configuration of a hybrid vibration isolator according to Embodiment 6 of the present invention. An acceleration sensor 110 is mounted on the base surface 109 instead of the acceleration sensor 105 having the intermediate mass 104. FIG. 6 is a block diagram showing a basic configuration of an actuator control system controlled by the control unit 120 of the vibration isolation strut 1 of FIG. In the above embodiment, for example, as shown in FIG. 1, the acceleration sensor 105 is arranged to monitor the acceleration of the intermediate mass 104, and the actuator control system of FIG. 3 uses the output of the acceleration sensor 105. but, as shown in FIG. 6, by using the output (Tsudotto) X _B of the acceleration sensor 110 mounted on the base surface 109 shown in the output (Tsudotto) X _P and 5 of the acceleration sensor 107 of the payload mounting surface 108, the intermediate the intermediate mass acceleration estimator 27 for estimating an acceleration (Tsudotto) X _F mass 104 may be configured to be disposed.

  With this configuration, it is not necessary to mount the acceleration sensor 105 for monitoring the acceleration of the intermediate mass 104, and the overall mass of the vibration isolation strut 1 can be suppressed. Further, even when the passive vibration isolation strut portion 111 is very small and compact and an acceleration sensor cannot be mounted, desired vibration isolation characteristics can be realized.

Embodiment 7 FIG.
The basic configuration of the vibration isolator according to Embodiment 7 of the present invention is the same as that of the above embodiment, but FIG. 7 shows the basic configuration of the actuator control system in the control by the control unit of the vibration isolation strut. In the first embodiment, the current controller 16 is mounted on the actuator control system, that is, the control unit 120 as shown in FIG. 3, but the current controller 16 may not be included as shown in FIG. .

The basic operation of the actuator control system is, for example, in the first embodiment shown in FIG. 3 by considering the phase delay due to the current controller 16 in the command value F ^* of the voice coil 101 calculated by the acceleration control system. , Improving control performance. However, in the actual configuration, if the delay of the generated force in the voice coil 101 can be ignored or within the range where the necessary vibration insulation characteristics can be realized, the current control loop is eliminated as shown in FIG. The actuator, that is, the voice coil 101 can be directly driven by the command value F ^* , and the control calculation load can be reduced. The entire current control including the current controller 16, the arithmetic unit 14, and the subtracter 15 can be omitted, and the entire circuit of the actuator control system can be simplified.

  As described above, according to the present invention, the acceleration of the intermediate mass can be monitored by attaching the acceleration sensor to the intermediate mass. In the conventional passive four-parameter vibration isolation strut, only by fine adjustment of the intermediate composite mass. The attenuation characteristic of −60 dB / dec in the high frequency band that was feasible can be easily realized regardless of the fine adjustment of the mass, and further band and vibration isolation can be achieved by combining with the control system. The effect can be improved.

  In addition, this invention is not limited to each said embodiment, It cannot be overemphasized that all the possible combinations of the characteristic of each embodiment are included.

  DESCRIPTION OF SYMBOLS 1 Vibration isolation strut 10, 14, 19 Calculation part, 11, 15, 20 Subtraction part, 12, 21 Acceleration controller, 13, 25 Adder, 16 Current controller, 18 Vibration isolator, 105a Relative displacement sensor, 26 Differential 27, intermediate mass acceleration estimator, 101 active actuator (voice coil), 102 first spring, 103 second spring, 104 intermediate mass (connection), 105, 107, 110 acceleration sensor (motion sensor), 105a Relative displacement sensor, 106 damper, 108 payload mounting surface, 109 base surface, 111 4-parameter vibration isolation strut part, 120 control part, 200 center axis, 201 shaft axis, 202 first end part, 203 second end part, 204 Base member, 205 End member, 206 First bellows, 207 Second bellow , 208 flange, 209 annular flow path, 210 volume chamber A, 211 volume chamber B, 212 third plate spring C, 213 third plate spring D, 214 first plate spring A, 215 second plate Spring B, 216 rigid member A, 217 rigid member B, 218 rigid member C, 219 rigid member D, 220 rigid member E, 221 rigid member F, 222 cover A, 223 cover B, 224 pivot A, 225 biaxial pivot B 226 strut end A, 227 strut end B, 231 magnet, 232 coil, 301 third spring, 302 second damper.

Claims (11)

A first spring provided between the base and the payload;
A second spring and a damper connected in series between the base and the payload in parallel with the first spring, and a connecting portion constituting an intermediate mass connecting the second spring and the damper A vibration absorbing part,
An actuator provided between the base and the payload to suppress the vibration of the payload with respect to the base;
A first motion sensor mounted on the payload;
A second motion sensor mounted on the connection portion of the vibration absorbing portion;
An actuator control system including a controller that controls the actuator to suppress vibration of the payload according to feedback signals from the first and second motion sensors;
A vibration isolator characterized by comprising:   The vibration isolation device according to claim 1, wherein the actuator control system includes a current control system for actuator drive control.   The vibration isolator according to claim 1, wherein the motion sensor is an acceleration sensor.   The vibration isolation device according to any one of claims 1 to 3, wherein the actuator is a non-contact actuator.   5. The vibration isolator according to claim 1, wherein the damper includes a fluid damper, and the intermediate mass includes the fluid mass of the damper in the control in the actuator control system.   6. The vibration isolator according to claim 1, wherein the motion sensor is a relative displacement sensor.   The vibration isolator according to any one of claims 1 to 4 and 6, wherein the damper is an electric electromagnetic damper or a viscoelastic damper using a viscoelastic body.   The vibration isolator according to claim 3, wherein PI control or P control is performed by acceleration control in the actuator control system.   In the actuator control system, the acceleration of the connection portion of the vibration absorbing portion is estimated from the acceleration from the first motion sensor mounted on the payload among the first and second motion sensors including the acceleration sensor. 4. The vibration isolator according to claim 3, wherein an acceleration estimator is provided and the second motion sensor is not required. The actuator comprises a voice coil;
The actuator control system is
The actuator is configured to perform PI control or P control with an acceleration controller for values that make the acceleration of the connection portion of the payload and the vibration absorbing portion obtained based on feedback signals of the first and second motion sensors 0 respectively. Acceleration control means for obtaining a force command value to
Current control means for generating an applied voltage to the voice coil with a current controller according to the characteristics of the voice coil after converting the force command value into a current command value;
The vibration isolator according to claim 1, comprising:   11. The vibration isolator according to claim 10, wherein the current control means is not required and a voltage applied to the voice coil is generated according to a force command value of the acceleration control means.

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