Active vibration isolation system and leveling method thereof

Abstract

The controller (100) executes a leveling control for sequentially operating the plurality of leveling mechanisms (4) so that each of the first displacements (z1) falls within a predetermined allowable range (R1) before the active vibration isolation system (S) is activated. When performing the leveling control, the controller (100) repeatedly executes a first step for determining the leveling mechanism (4) corresponding to the support position (P) at which the deviation (D1) between the first displacement (z1) and the allowable range (R1) is maximum among the plurality of leveling mechanisms (3), and a second step for operating the leveling mechanism (4) determined in the first step so as to reduce the deviation (D1).

Description

Technical Field

[0001] The present disclosure relates to an active vibration isolation system and a leveling method thereof. Background Art

[0002] For example, Patent Document 1 discloses an active vibration isolation device including a height adjustment mechanism as a leveling mechanism. Specifically, the active vibration isolation device includes: height adjustment mechanisms arranged at four corners of a housing; four coil springs arranged via the height adjustment mechanisms; a platform supported at the four corners by the coil springs; and a controller for operating each height adjustment mechanism.

[0003] According to Patent Document 1, the controller controls each height adjustment mechanism to vertically displace the lower end of each coil spring. The controller adjusts the height position of the platform by displacing the lower end of each coil spring.

[0004] Patent Document 2 discloses a vibration-proof and leveling device as a leveling mechanism. Specifically, a plurality of the devices are arranged at predetermined positions below a workbench and used to support the workbench.

[0005] According to Patent Document 2, since the working fluid can be supplied to each device from the adjustment device disposed at one location, the operator can adjust a plurality of vibration-proofing and leveling devices from one location.

[0006] Patent Document 1: Japanese Patent Publication No. 2010-127391

[0007] Patent Document 2: Japanese Patent Publication No. 2005-054808 Summary of the invention

[0008] -Technical problem to be solved by the invention-

[0009] In a general active vibration isolation device, it is conceivable that the height of the platform is adjusted (leveled) before performing control for suppressing vibration of a supported object placed on the platform (hereinafter also referred to as "vibration isolation control").

[0010] In this case, in order to achieve more appropriate vibration isolation control, it is required to perform leveling as accurately and well-balanced as possible. As a leveling mechanism that meets such a requirement, the height adjustment mechanism disclosed in the above-mentioned Patent Document 1 can be considered.

[0011] Here, when the mechanism disclosed in Patent Document 1 is used, in order to complete the leveling in the shortest possible time, a case where the leveling mechanisms are operated simultaneously has been studied.

[0012] However, as disclosed in Patent Document 1, when the height of the platform is adjusted by vertically displacing the lower ends of the coil springs, the lower end positions of the coil springs that optimize the height of the platform can be changed according to the magnitude of the load acting on the coil springs.

[0013] For example, when a large load acts on the coil spring, the deflection of the coil spring also increases, so the lower end position of the coil spring needs to be lifted further upward compared to when a smaller load acts on the coil spring.

[0014] On the other hand, when a plurality of leveling mechanisms are operated simultaneously, the load distribution from the supported body on the platform changes by operating one leveling mechanism, and the load acting on the coil springs attached to other leveling mechanisms may change in conjunction with the operation of one leveling mechanism.

[0015] In this case, with regard to the coil spring attached to the other leveling mechanism, the most preferred lower end position will change at any time as the load changes, which may hinder the convergence of the leveling in the leveling mechanism (other leveling mechanism), and may even hinder the convergence of multiple leveling mechanisms as a whole.

[0016] That is, there is a possibility that one leveling mechanism and the other leveling mechanism may affect each other's leveling work, resulting in the possibility that the leveling work of both parties may not be completed.

[0017] The present disclosure is made to solve the above-mentioned problems, and its purpose is to achieve leveling that is as accurate and well-balanced as possible without destroying convergence.

[0018] -Technical solutions to solve technical problems-

[0019] The first aspect of the present disclosure relates to an active vibration isolation system, comprising one or more active vibration isolation devices arranged on a prescribed surface, and a controller for controlling the one or more active vibration isolation devices respectively, wherein the active vibration isolation system supports a load from below through the one or more active vibration isolation devices. In the active vibration isolation system, the one or more active vibration isolation devices respectively include a platform, a plurality of elastic bodies, a plurality of leveling mechanisms, and a plurality of platform displacement sensors, wherein the platform is used to carry the supported object, the plurality of elastic bodies are arranged at a plurality of mutually different supporting positions, and the platform is elastically supported from below at each supporting position, the plurality of leveling mechanisms are arranged in a manner corresponding to the plurality of elastic bodies respectively, support the corresponding elastic bodies from below, and displace the platform in an up-down direction via the elastic bodies, and the plurality of platform displacement sensors are arranged in a manner corresponding to the plurality of elastic bodies respectively, and detect a first displacement representing the displacement of the platform relative to the prescribed surface at each supporting position.

[0020] According to a first aspect of the present disclosure, the controller performs leveling control before the active vibration isolation system is started. The leveling control causes the multiple leveling mechanisms to operate in sequence based on detection signals of the multiple platform displacement sensors so that the first displacement falls within a specified allowable range, respectively. The controller repeatedly performs a first step and a second step when performing the leveling control. The first step determines a leveling mechanism among the multiple leveling mechanisms that corresponds to a support position where the deviation between the first displacement and the allowable range is the largest, and the second step causes the leveling mechanism determined according to the first step to operate so as to reduce the deviation.

[0021] According to the first aspect, by making each leveling mechanism work in sequence, the influence of the operation of one leveling mechanism on the operation of other leveling mechanisms can be suppressed as much as possible. As a result, the leveling can be achieved as accurately and well-balanced as possible without destroying the convergence of the leveling control. By suppressing the seeking in the leveling control, as a result, the leveling control can also be completed more quickly.

[0022] According to the second aspect of the present disclosure, it may be as follows: the controller is configured to perform the leveling control in a specified first mode before performing the leveling control in a second mode composed of the first step and the second step. When performing the leveling control in the first mode, the controller, after adjusting the first displacement of all supporting positions to outside the allowable range by operating all of the multiple leveling mechanisms, performs a third step of operating all of the multiple leveling mechanisms simultaneously so as to reduce the deviation from the allowable range.

[0023] According to the second aspect, the leveling control in the first mode is executed when relatively rough control can be tolerated, such as immediately after the start of the leveling control, and thereafter the leveling control in the second mode is executed when a predetermined accuracy or higher is required.

[0024] In this way, by distinguishing the control modes to be used according to the progress of the leveling control, the leveling can be performed as quickly as possible and as accurately as possible. As a result, the performance of the leveling control is significantly improved.

[0025] According to the third aspect of the present disclosure, it may be as follows: the controller is configured to perform the leveling control in a specified third mode after performing the leveling control in a second mode composed of the first step and the second step. When performing the leveling control in the third mode, the controller repeats the first step, the second step and the fourth step. After the second step is completed, the fourth step returns to the state before the first step, so that all the multiple leveling mechanisms are in a non-working state, and then standby for a specified time.

[0026] According to the third aspect, the leveling control in the second mode is performed in the middle stage of the leveling control, and the leveling control in the third mode is performed in the final stage of the leveling control. By performing the third mode, the influence of the inertial force accompanying the operation of each leveling mechanism can be suppressed as much as possible. The third mode provides more accurate leveling than the second mode.

[0027] In this way, by selecting and using the control mode according to the progress of the leveling control, it is possible to achieve both the relatively rapid leveling of the second mode and the relatively accurate leveling of the third mode. As a result, the performance of the leveling control is significantly improved.

[0028] According to a fourth aspect of the present disclosure, when the proportion of the leveling mechanisms whose first displacement falls within the allowable range among the plurality of leveling mechanisms is greater than a specified proportion, the controller shifts from the second mode to the third mode.

[0029] According to the fourth aspect, the second mode can be smoothly shifted to the third mode according to the progress of the leveling control.

[0030] According to the fifth aspect of the present disclosure, it may be as follows: if the leveling mechanism determined according to the first step is taken as a specific leveling mechanism, and the two leveling mechanisms adjacent to the specific leveling mechanism on the specified plane are respectively taken as adjacent leveling mechanisms, then the controller calculates the difference of the first displacement between the two adjacent leveling mechanisms, and when performing the second step, when the difference is less than a specified value, the controller only makes the specific leveling mechanism work, and on the other hand, when the difference is greater than the specified value, the controller makes one of the two adjacent leveling mechanisms whose value of the first displacement is close to the value of the first displacement in the specific leveling mechanism work together with the specific leveling mechanism.

[0031] According to the fifth aspect, by activating the adjacent leveling mechanism in addition to the specific leveling mechanism, the stroke (displacement) of the elastic body associated with the specific leveling mechanism can be suppressed. In each active vibration isolating device, the deflection difference between the elastic bodies can be suppressed.

[0032] It should be noted that if a plurality of leveling mechanisms are operated simultaneously as described above, seeking may occur. However, in the present disclosure, since specific leveling mechanisms are operated one by one in sequence, the occurrence of seeking is suppressed compared to a configuration in which randomly selected leveling mechanisms are operated simultaneously.

[0033] Although the adjacent leveling mechanism and the specific leveling mechanism are operated simultaneously, the leveling mechanisms located at non-adjacent positions (eg diagonal positions) in each vibration isolation device are not operated simultaneously. This also works effectively in suppressing the occurrence of seeking.

[0034] According to the sixth aspect of the present disclosure, it may be as follows: the one or more active vibration isolation devices further include: a plurality of spring seats and spring displacement sensors, respectively, the plurality of spring seats are respectively arranged in the plurality of leveling mechanisms, respectively supporting the elastic bodies, the spring displacement sensors are arranged in a manner corresponding to the plurality of elastic bodies, respectively, and detect a second displacement representing the displacement of the spring seat at each supporting position relative to the specified surface; the controller determines the magnitude relationship of the second displacement between the plurality of elastic bodies for each of the active vibration isolation devices, and executes a deflection difference elimination process to make the respective leveling mechanisms work to reduce the difference when the difference in the second displacement is above a specified value, and the controller executes the deflection difference elimination process in priority to the leveling control.

[0035] According to the sixth aspect, by performing control based on the second displacement in addition to the first displacement, the deflection difference of each elastic body can be suppressed. Suppression of the deflection difference is useful for achieving well-balanced leveling corresponding to the load distribution of the supported body and ensuring the durability of each elastic body.

[0036] The seventh aspect of the present disclosure relates to a leveling method for an active vibration isolation system, which includes one or more active vibration isolation devices arranged on a specified surface, and a controller that controls the one or more active vibration isolation devices respectively. The active vibration isolation system uses the one or more active vibration isolation devices to support a supported object from below. In the leveling method, the one or more active vibration isolation devices respectively include: a platform, a plurality of elastic bodies, a plurality of leveling mechanisms and a plurality of platform displacement sensors, the platform is used to carry the supported body, the plurality of elastic bodies are arranged at a plurality of mutually different supporting positions, and the platform is elastically supported from below at each supporting position, the plurality of leveling mechanisms are arranged in a manner corresponding to the plurality of elastic bodies, respectively support the corresponding elastic bodies from below, and displace the platform in the up and down directions via the elastic bodies, the plurality of platform displacement sensors are arranged in a manner corresponding to the plurality of elastic bodies, respectively detect a first displacement representing the displacement of the platform at each supporting position relative to the specified surface, and the controller performs leveling control before the active vibration isolation system is started, and the leveling control causes the plurality of leveling mechanisms to operate in sequence based on the detection signals of the plurality of platform displacement sensors so that the first displacements fall within a specified allowable range.

[0037] According to the seventh aspect, in the leveling method, when performing the leveling control, the controller repeatedly executes a first step and a second step, wherein the first step determines a leveling mechanism among the multiple leveling mechanisms corresponding to a support position where the deviation between the first displacement and the allowable range is the largest, and the second step operates the leveling mechanism determined according to the first step to reduce the deviation.

[0038] According to the seventh aspect, by making each leveling mechanism work in sequence, the influence of the operation of one leveling mechanism on the operation of other leveling mechanisms can be suppressed as much as possible. As a result, it is possible to achieve the most accurate and well-balanced leveling without destroying the convergence of the leveling control. By suppressing the seeking in the leveling control, as a result, the leveling control can also be completed more quickly.

[0039] - Effects of the Invention -

[0040] As described above, according to the present disclosure, it is possible to achieve leveling that is as accurate and balanced as possible without destroying convergence. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A diagram showing the general structure of an active vibration isolation system;

[0042] Figure 2 A diagram showing the internal structure of each active vibration isolation device 1;

[0043] Figure 3 A longitudinal sectional view showing the structure of each leveling mechanism;

[0044] Figure 4 A diagram showing the electrical connection between the controller and each vibration isolation device;

[0045] Figure 5 A flowchart showing an overview of leveling control;

[0046] Figure 6 A flowchart showing a process associated with the first mode;

[0047] Figure 7 A flowchart showing a process associated with the second mode;

[0048] Figure 8 A flowchart showing a leveling process common to the second mode and the third mode;

[0049] Fig. 9 A flowchart showing a process associated with the third mode;

[0050] Fig.10 A flowchart showing a process associated with the third mode;

[0051] Fig.11 Flowchart showing the deflection difference elimination process. DETAILED DESCRIPTION

[0052] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the following description is only for example.

[0053] (Overall structure of active vibration isolation system)

[0054] Figure 1 1 is a schematic diagram showing the structure of an active vibration isolation system S (hereinafter, simply referred to as a “vibration isolation system”) according to the present embodiment. Figure 2 1 is a diagram showing the internal structure of each active vibration isolation device 1 .

[0055] The vibration isolation system S includes: one or more active vibration isolation devices 1 (hereinafter referred to as "vibration isolation devices") arranged on a predetermined surface, and a controller 100 for controlling the one or more vibration isolation devices 1. The vibration isolation system S supports a supported object 300 as a supported body from below (along one direction of the Z direction described later) through the one or more vibration isolation devices 1.

[0056] In the example, one or more vibration isolation devices 1 are provided in four. The four vibration isolation devices 1 are respectively provided on a setting surface F as a predetermined surface. The setting surface F in the present embodiment extends in a substantially horizontal direction. Hereinafter, two horizontal directions extending along the setting surface F and orthogonal to each other are respectively referred to as the X direction and the Y direction, and the vertical direction orthogonal to the setting surface F is referred to as the Z direction. The Z direction is sometimes also referred to as the height direction or the up-down direction.

[0057] The four vibration isolation devices 1 are all active vibration isolation devices, and by properly operating the actuators of each device, the vibration transmission from the installation surface F to the load 300 can be cut off. Each vibration isolation device 1 can perform so-called active vibration isolation control consisting of vibration isolation feedback control and vibration isolation feedforward control described later.

[0058] The four vibration isolating devices 1 elastically support the mounted object 300 with respect to the installation surface F, thereby also functioning as passive vibration isolating devices.

[0059] The support 300 in this embodiment includes: a precision device 301 such as a semiconductor manufacturing device or an electron microscope which is preferably protected from vibration, and a workbench 302 for placing the precision device 301. The workbench 302 has four legs. Each leg of the workbench 302 is supported from below by the vibration isolation device 1.

[0060] It should be noted that the structure of the support 300 is not limited to this example. For example, a plate-shaped member may be used instead of the workbench 302. Alternatively, the rectangular device may be directly supported by four vibration isolators 1 without using the workbench 302 or the plate-shaped member.

[0061] The four vibration isolating devices 1 also function as a "mount" for supporting the load 300. Therefore, when distinguishing the four vibration isolating devices 1, each vibration isolating device 1 is sometimes referred to as a "first mount 1A", "second mount 1B", "third mount 1C" and "fourth mount 1D".

[0062] In order to support the load 300 in a well-balanced manner, the four vibration isolating devices 1 are of the same type (same size, same performance). The four vibration isolating devices 1 are each configured as a rectangular thin box whose dimension in the Z direction is shorter than that in the XY direction. Each vibration isolating device 1 has a lower plate 11 forming the bottom wall of the thin box, a side plate 12 forming the side wall of the thin box, and an upper plate 13 forming the top plate of the thin box. The lower plate 11 is supported from below by the installation surface F.

[0063] The upper plate 13 is formed in a flat thin plate shape, and functions as a surface plate for placing the object 300. The upper plate 13 basically has a substantially square shape having four corners.

[0064] Each vibration isolation device 1 includes: four elastic bodies 3, four leveling mechanisms 4, four platform displacement sensors 5, four spring displacement sensors 6, six actuators 2, three (in Figure 2 Only one is shown in the figure) a foundation side vibration sensor 7 (FF sensor), six load side vibration sensors 8 (FB sensors) as the second vibration detection unit, and a unique controller 9 for each vibration isolation device 1. Among them, the unique controller 9 is a control unit unique to each vibration isolation device 1. These components are stored in the internal space divided by the lower plate 11, the side plate 12 and the upper plate 13.

[0065] Hereinafter, the structure of each vibration isolating device 1 will be described in detail. It should be noted that the following description is common among the four vibration isolating devices 1 except for special descriptions.

[0066] (Details of each active vibration isolation device)

[0067] The four elastic bodies 3 are arranged at a plurality of different (the same number as the elastic bodies 3 in this embodiment) support positions P. The four elastic bodies 3 elastically support the upper plate 13 at each support position P from below.

[0068] The plurality of support positions P in the present embodiment correspond to four corners in the space between the lower plate 11 and the upper plate 13. At one support position P, one elastic body 3 is arranged.

[0069] Specifically, the four elastic bodies 3 are interposed between the lower plate 11 and the upper plate 13 (more specifically, between the upper surface of the lower plate 11 and the lower surface of the upper plate 13 ), and are respectively extended and retracted in the Z direction. Each elastic body 3 elastically supports the upper plate 13 and the load 300 relative to the lower plate 11 .

[0070] like Figure 3 As shown in FIG. 1 , each elastic body 3 according to the present embodiment is formed of a coil spring. Each elastic body 3 formed of a coil spring is arranged so that its expansion and contraction direction is substantially parallel to the Z direction.

[0071] In detail, in the present embodiment, each elastic body 3 is composed of unequally spaced springs. In this case, each elastic body 3 has a progressive characteristic in which its spring constant increases approximately in direct proportion to the increase in the load caused by the weight of the carrier 300. Therefore, even if the precision device 301 is changed to other devices, resulting in a change in the weight of the carrier 300, the natural vibration frequency of the spring system remains approximately constant. As a result, a higher vibration isolation effect can be obtained through active vibration isolation control, regardless of changes in the equipment. It should be noted that each elastic body 3 can also be composed of equidistant springs.

[0072] Figure 3: is a longitudinal sectional view showing the structure of each leveling mechanism 3. The four leveling mechanisms 4 are arranged to correspond to the four elastic bodies 3 one by one. Here, one leveling mechanism 4 corresponds to one elastic body 3 and one supporting position P. The four leveling mechanisms 4 support the elastic bodies 3 corresponding thereto from below, and displace the upper plate 13 in the Z direction via the elastic bodies 3.

[0073] like Figure 2 and Figure 3 As shown, each leveling mechanism 4 includes a screw shaft 41 , a spring seat 42 , a driven gear 43 , an intermediate gear 44 , and an electric motor 45 .

[0074] In detail, the screw shaft 41 extends upward from the lower plate 11 and is arranged to be rotatable around the Z axis. The spring seat 42 is screwed with the screw shaft 41 and holds the lower end of the elastomer 3 (more generally, one end in the expansion and contraction direction of the elastomer 3). The driven gear 43 is arranged below the spring seat 42, fixed on the screw shaft 41, and rotates integrally with the screw shaft 41. The intermediate gear 44 meshes with the driven gear 43. The electric motor 45 has a rotating shaft (not shown) to which a pinion is fixed. The pinion of the electric motor 45 is connected to the intermediate gear 44 in a manner that can transmit power.

[0075] The electric motor 45 is electrically connected to the controller 100 and operates by receiving a control signal from the controller 100. When the electric motor 45 operates, the rotating shaft rotates. When the electric motor 45 rotates the rotating shaft, the rotation rotates the driven gear 43 via the intermediate gear 44. With the rotation of the driven gear 43, the screw shaft 41 also rotates integrally. The spring seat 42 moves up and down by the rotation of the screw shaft 41.

[0076] For example, when one of the four spring seats 42 is displaced upward, the elastic body 3 held by the spring seat 42 can be lifted upward or compressed in the vertical direction. By lifting the elastic body 3 against the load of the support 300, the upper plate 13 can be displaced upward at the support position P corresponding to the elastic body 3.

[0077] Similarly, when one of the four spring seats 42 is displaced downward, the elastic body 3 held by the spring seat 42 can be lowered downward or the elastic body 3 can be extended in the vertical direction. By lowering the elastic body 3 downward, the upper plate 13 can be displaced downward at the supporting position P corresponding to the elastic body 3.

[0078] It should be noted that, although not shown in the drawings, each leveling mechanism 4 further includes a slider that guides the spring seat 42 to slide in the up-down direction.

[0079] The four platform displacement sensors 5 are arranged to correspond to the four elastic bodies 3, respectively. Here, one platform displacement sensor 5 corresponds to one elastic body 3, one support position P, and one leveling mechanism 4. The four platform displacement sensors 5 respectively detect the displacement of the upper plate 13 at each support position P relative to the setting surface F (specifically, the displacement in the Z direction). The four platform displacement sensors 5 are respectively electrically connected to the controller 100, so as to input an electrical signal corresponding to the detection result to the controller 100.

[0080] In detail, each platform displacement sensor 5 is composed of a magnet Hall element sensor. The magnet constituting the Hall element sensor is arranged on the upper plate 13. After the magnet and the upper plate 13 move up and down integrally, each platform displacement sensor 5 detects the change in magnetic force caused by the up and down movement. The electrical signal corresponding to the change in magnetic force represents the displacement of the upper plate 13 relative to the setting surface F (hereinafter referred to as "displacement of the upper plate 13", or "first displacement"). The first displacement is Figure 3 The symbol z1 is shown in .

[0081] It should be noted that the "first displacement" mentioned here is defined as a value with a sign so that it can be distinguished whether the detection object is located above or below. The same applies to the "second displacement" described later.

[0082] If the weight of the load 300 changes, the corresponding relationship between the displacement of the upper plate 13 and the displacement of the spring seat 42 relative to the setting surface F in the vertical direction (hereinafter referred to as "displacement of the spring seat 42" or second displacement) will also change. After the weight of the load 300 changes, even if the displacement of the upper plate 13 remains unchanged, the displacement of the spring seat 42 that realizes it may not remain unchanged. Figure 3 The symbol z2 is shown in .

[0083] For example, when the load 300 is heavy, the elastic body 3 is further compressed compared to when it is light, so it is necessary to set the height position of the spring seat 42 relatively on the upper side to lift the elastic body 3 upward.

[0084] Therefore, in order to make each leveling mechanism 4 operate more appropriately, it is conceivable to perform control based not only on the displacement of the upper plate 13 but also on the displacement of the spring seat 42 .

[0085] The four spring displacement sensors 6 are arranged in a manner corresponding to the four elastic bodies 3, respectively. Here, one spring displacement sensor 6 corresponds to one elastic body 3, one support position P, one leveling mechanism 4, and one platform displacement sensor 5. The four spring displacement sensors 6 respectively detect the displacement of the spring seat 42 at each support position P relative to the installation surface F (specifically, the displacement in the Z direction). The four spring displacement sensors 6 are respectively electrically connected to the controller 100, so that the electrical signals corresponding to the detection results are input to the controller 100. Each spring displacement sensor 6 can also be composed of a potentiometer, for example.

[0086] In each vibration isolation device 1 , one elastic body 3 , one leveling mechanism 4 , one platform displacement sensor 5 , and one spring displacement sensor 6 correspond to one supporting position P.

[0087] In other words, each vibration isolation device 1 can be regarded as including four displacement modules M1, M2, M3, and M4, which are respectively connected to an elastic body 3, a leveling mechanism 4, a platform displacement sensor 5, and a spring displacement sensor 6 at four supporting positions P.

[0088] Below, from Figure 2 The lower left corner of is facing clockwise, and they are also referred to as the first displacement module M1, the second displacement module M2, the third displacement module M3 and the fourth displacement module M4.

[0089] For example, the first displacement module M1 is at the corresponding support position P ( Figure 2 The upper plate 13 is supported from below at the lower left corner, and the height of the upper plate 13 is adjusted at the supporting position P.

[0090] On the other hand, the six actuators 2 each apply a control force to the supported object 300 via the upper plate 13. Each actuator 2 can be constituted by a linear motor, for example.

[0091] Specifically, the six actuators 2 are arranged to surround the center O (the intersection point where the diagonal lines of the upper plate 13 intersect) of the corresponding vibration isolation device 1 along the circumferential direction. The six actuators 2 constitute three actuator pairs, and each actuator pair is composed of two actuators 2 whose lines of action of the control force extend parallel to each other (see Figure 2 Symbols C1, C2, C3 in it).

[0092] Although detailed illustration is omitted, the lines of action of the control force of each actuator 2 are arranged so as to be inclined with respect to the lower plate 11 , the side plate 12 , and the upper plate 13 .

[0093] The three FF sensors 7 are arranged on the lower plate 11 in a state where the detection directions thereof are inclined with respect to the installation surface F. The inclination angle of the action direction of each actuator 2 is equal to the inclination angle of the detection direction of each FF sensor 7 .

[0094] The FF sensor 7 is an acceleration sensor. The FF sensor 7 detects vibration acceleration as the vibration state of the installation surface F. The three FF sensors 7 respectively detect the vibration acceleration of the installation surface F in the detection direction, and as a result, the vibration acceleration is detected in three translation directions (X, Y, and Z directions) including the vertical direction and the horizontal direction of the installation surface F and three rotation directions (θx, θy, and θz directions) around each translation axis.

[0095] The six FB sensors 8 are arranged in a state where the detection directions thereof are tilted relative to the installation surface F, in the same direction as the action directions of the actuators 2. The tilt angle of the action direction of the actuator 2 is equal to the tilt angle of the detection direction of the FB sensor 8. Each FB sensor 8 may also be provided integrally with the corresponding actuator 2.

[0096] Each FB sensor 8 is an acceleration sensor. The FB sensor 8 detects vibration acceleration as the vibration state of the load 300. The six FB sensors 8 detect the vibration acceleration of the load 300 in the detection direction respectively, and as a result, the vibration acceleration is detected in three translation directions (X, Y, and Z directions) including the vertical direction and the horizontal direction of the load 300 and three rotation directions (θx, θy, and θz directions) around each translation axis.

[0097] The unique controller 9 is disposed, for example, at the center of the lower surface of the upper plate 13. The three FF sensors 7 and the six FB sensors 8 input detection signals to the unique controller 9. The unique controller 9 controls each actuator 2 based on these detection signals.

[0098] Specifically, the intrinsic controller 9 outputs a control signal to each actuator 2 based on the signal input from each FB sensor 8, that is, based on the vibration acceleration of the load 300 detected by each FB sensor 8, to perform feedback control on each actuator 2 so as to apply a control force to the load 300 for reducing the vibration of the load 300. The intrinsic controller 9 performs the so-called vibration isolation feedback control.

[0099] For example, the inherent controller 9 performs filtering processing on the integrated value of the vibration acceleration and then multiplies it by the feedback gain, and takes the inverse of the sum obtained by the addition as the control input to the actuator 2.

[0100] The intrinsic controller 9 outputs a control signal to each actuator 2 based on the signal input from each FF sensor 7, that is, based on the vibration acceleration of the installation surface F detected by each FF sensor 7, to perform feedforward control on each actuator 2 so as to apply a control force to the support 300 for reducing the vibration transmitted from the installation surface F to the support 300. The intrinsic controller 9 performs the so-called vibration isolation feedforward control.

[0101] For example, the inherent controller 9 performs filtering processing on the vibration from the installation surface F, multiplies the result by a feedforward gain, and adds the result to the control input to the actuator 2 .

[0102] Among the processes performed by the intrinsic controller 9, at least the processes related to the vibration isolation feedback control and the vibration isolation feedforward control are independent between the vibration isolation devices 1. The intrinsic controller 9 at least does not send or receive electrical signals related to these controls between the vibration isolation devices 1.

[0103] (Controller)

[0104] Figure 4 1 is a diagram showing the electrical connection between the controller 100 and each vibration isolation device 1 .

[0105] Unlike the inherent controller 9, the controller 100 is shared by the four vibration isolation devices 1. The controller 100 includes a CPU, a memory, and an input / output bus. The controller 100 is electrically connected to each vibration isolation device 1 via at least the same number of cables 200 as the vibration isolation device 1. In the example, one cable is shown for simplicity, but each cable 200 may also be composed of two paths, an input cable and an output cable.

[0106] It can also be composed of one or more cables.

[0107] By electrically connecting via the cables 200, electric signals can be transmitted and received between the controller 100 and each vibration isolation device 1. As a communication protocol in this case, for example, CAN (Controller Area Network) can be used. Wireless communication can be used instead of wired communication. In this case, a so-called wireless LAN can be used.

[0108] As described above, each vibration isolation device 1 has four displacement modules M1 to M4. There are a total of 16 displacement modules in the entire active vibration isolation system S. The controller 100 assigns different IDs to these displacement modules (a total of 16 IDs in the example).

[0109] The controller 100 assigns a different ID to each vibration isolation device 1 , so that the operation of the displacement modules can be coordinated between different vibration isolation devices 1 when performing the leveling control described later.

[0110] By configuring in this way, for example, the influence of operating the first displacement module M1 of the first base 1A can affect the operation of the second displacement module M2 of the third base 1C.

[0111] This allows the upper surfaces of the upper plates 13 to be set to the same height between different vibration isolation devices 1. Such a setting should be performed in advance before the active vibration isolation control.

[0112] Hereinafter, the IDs assigned to the 16 displacement modules M1 to M4 are also referred to as “channels.” Each channel is linked to an elastic body 3 , a leveling mechanism 4 , a platform displacement sensor 5 , a spring displacement sensor 6 , and a support position P.

[0113] The controller 100 specifies a channel when outputting various control signals, and can operate the leveling mechanism 4 at the support position P linked to the channel. The controller 100 acquires the channel of the input source when receiving various detection signals, and can grasp the support position P where the detection signal is obtained.

[0114] exist Figure 4 In the example shown, the first displacement module M1 of the first base 1A is assigned a channel "chA1", the second displacement module M2 of the first base 1A is assigned a channel "chA2", the third displacement module M3 of the first base 1A is assigned a channel "chA3", and the fourth displacement module M4 of the first base 1A is assigned a channel "chA4".

[0115] Similarly, the first displacement module M1 of the second base 1B is assigned channel "chB1", the second displacement module M2 of the second base 1B is assigned channel "chB2", the third displacement module M3 of the second base 1B is assigned channel "chB3", and the fourth displacement module M4 of the second base 1B is assigned channel "chB4".

[0116] Similarly, the first displacement module M1 of the third base 1C is assigned channel "chC1", the second displacement module M2 of the third base 1C is assigned channel "chC2", the third displacement module M3 of the third base 1C is assigned channel "chC3", and the fourth displacement module M4 of the third base 1C is assigned channel "chC4".

[0117] Similarly, the first displacement module M1 of the fourth base 1D is assigned channel "chD1", the second displacement module M2 of the fourth base 1D is assigned channel "chD2", the third displacement module M3 of the fourth base 1D is assigned channel "chD3", and the fourth displacement module M4 of the fourth base 1D is assigned channel "chD4".

[0118] The controller 100 can perform initial setting (channel assignment process) of these channels by transmitting and receiving signals with each vibration isolating device 1 via the cables 200. When performing the channel assignment process, the number of cables 200 may be set to be greater than the number of vibration isolating devices 1.

[0119] When performing the channel assignment process, the controller 100 selects one of the plurality of cables 200 and outputs an electrical signal via the cable 200. When a signal corresponding to the electrical signal is returned to the controller 100, the controller 100 determines that the vibration isolation device 1 is connected to the cable 200. The controller 100 sets the channel in accordance with the order in which the cables 200 are selected.

[0120] In the case of this embodiment, the controller 100 determines that the vibration isolation device 1 connected to the first selected cable 200 is the first base 1A, and sets the base identification ID "ChA". Then, the four displacement modules M1 to M4 included in the vibration isolation device 1 determined to be the first base 1A are assigned channels "chA1", "chA2", "chA3" and "chA4".

[0121] Next, the controller 100 determines that the vibration isolation device 1 connected to the second selected cable 200 is the second base 1B, and sets the base identification ID "ChB". Then, the four displacement modules M1 to M4 included in the vibration isolation device 1 determined to be the second base 1B are assigned channels "chB1", "chB2", "chB3" and "chB4".

[0122] The same applies to the third base 1C and the fourth base 1D.

[0123] Then, the controller 100 outputs an electrical signal via the fifth selected cable 200. When four vibration isolation devices 1 are used as in the present embodiment, the signal does not return to the controller 100. In this case, the controller 100 determines that there is no fifth vibration isolation device 1, and determines that the total number of channels is 4×4=16. The calculation of the total number of channels is useful in the leveling process described later.

[0124] It should be noted that the number of displacement modules M1 to M4 included in each vibration isolation device 1 (four in this embodiment) and the relative positional relationship between the displacement modules M1 to M4 are stored in advance in the controller 100. The relative positional relationship between the displacement modules M1 to M4 includes information indicating which displacement module in each vibration isolation device 1 is adjacent to a specified displacement module (for example, the second displacement module M2 and the fourth displacement module M4 are adjacent to the first displacement module M1).

[0125] The controller 100 performs a predetermined leveling control when the active vibration isolation system S is activated. The leveling control is to sequentially operate the plurality of leveling mechanisms 4 based on detection signals from the plurality of platform displacement sensors 5 so that the displacement of the upper plate 13 relative to the installation surface F falls within a predetermined allowable range.

[0126] It should be noted that the “activation of the active vibration isolation system S” mentioned here refers to adjustment to a state where the aforementioned vibration isolation feedback control and vibration isolation feedforward control can be started.

[0127] When the predetermined threshold value (first threshold value) is set to T1, the "allowable range" referred to here is a numerical range based on the first threshold value such as R1 = T1 ± ΔT1. If the displacement (first displacement) of the upper plate 13 relative to the installation surface F is set to z1, for example, then when T1-ΔT1≤z1≤T1+ΔT1 is satisfied, the controller 100 determines that the first displacement z1 falls within the allowable range R1. The first threshold value T1 is the same as the first displacement z1, and is shown in Figure 3 .

[0128] The size of the allowable range is stored in advance in the controller 100. The size of the allowable range is common to the four vibration isolation devices 1.

[0129] This leveling control is performed before the start of active vibration isolation control consisting of vibration isolation feedback control and vibration isolation feedforward control. The performance requirements in active vibration isolation control and the configuration of leveling control for satisfying the requirements are described in detail below.

[0130] (Problems involved in leveling control)

[0131] In order to more appropriately perform the active vibration isolation control as described above, it is conceivable to perform leveling as accurately and well-balanced as possible by using the leveling mechanism 4 configured as described above.

[0132] For example, when the load 300 is placed on the upper plate 13, it is sometimes required to make the upper surface of the upper plate 13 coincide with the horizontal plane, or to set the upper plates 13 of the four vibration isolation devices 1 to the same height. Such setting should be performed before the active vibration isolation control.

[0133] The position of the upper plate 13 can be pre-adjusted by the leveling control. By performing the leveling control, the height position (position observed in the Z direction) of each elastic body 3, especially the lower end of each elastic body 3, is displaced up and down. By this displacement, the initial height of the upper plate 13 can be adjusted. The height adjustment by the leveling control is achieved by operating the corresponding leveling mechanism 4 (one of the four displacement modules M1 to M4) at each support position P.

[0134] In this case, the height of the upper plate 13 can be optimized by changing the lower end position of the elastic body 3 according to the magnitude of the load acting on the elastic body 3 for operating the elastic body 3 .

[0135] As described above, when a large load acts on the elastic body 3 , the elastic body 3 expands and contracts to a greater extent, and therefore the lower end position of the elastic body 3 needs to be lifted further upward compared to a case where a relatively small load acts on the elastic body 3 .

[0136] On the other hand, when multiple leveling mechanisms 4 are operated simultaneously, by operating one leveling mechanism 4, the load distribution from the carrier 300 on the upper plate 13 will change, and the load acting on the elastic body 3 attached to other leveling mechanisms 4 may change in conjunction with the operation of one leveling mechanism 4.

[0137] In this case, with respect to the elastic body 3 attached to other leveling mechanisms 4, its optimal lower end position will change at any time as the load changes, which may hinder the convergence of the leveling in the leveling mechanism 4 (other leveling mechanisms), and may even hinder the convergence of the four leveling mechanisms 4 as a whole.

[0138] That is, there is a risk that one leveling mechanism 4 and the other leveling mechanism 4 will affect each other's leveling work, and the leveling work of both parties may not converge. Such an influence occurs between the leveling mechanisms 4 located at diagonal positions in each vibration isolation device 1 (for example, Figure 2 The first displacement module M1 and the third displacement module M3, and the second displacement module M2 and the fourth displacement module M4) are particularly worrying.

[0139] Therefore, the inventors of the present application have studied the configuration of the leveling control and have resolved the above concerns. Specifically, the controller 100 according to the present embodiment repeatedly executes a predetermined first step and a second step when performing the leveling control.

[0140] In the first step, the controller 100 identifies the leveling mechanism 4 (hereinafter also referred to as “specific leveling mechanism”) corresponding to the support position P having the largest deviation between the first displacement z1 and the allowable range R1 among the plurality of (16 in the example) leveling mechanisms 4 .

[0141] It should be noted that the controller 100 can use, for example, the difference between the first threshold value T1 and the first displacement z1 (D1=|T1-z1|) as an indicator of the deviation between the first displacement z1 and the allowable range R1. Figure 3 Shown in.

[0142] In the first step, the controller 100 determines a leveling mechanism 4 from the entire active vibration isolation system S, instead of determining a leveling mechanism 4 for each vibration isolation device 1 .

[0143] In the next second step, the controller 100 displaces the leveling mechanism 4 determined in the first step so as to reduce the deviation D1.

[0144] It should be noted that the controller 100 “repeatedly executes the first step and the second step” does not mean that the leveling mechanisms 4 are operated simultaneously, but means that the leveling mechanisms 4 are operated sequentially.

[0145] By operating each leveling mechanism 4 in sequence, the influence of the operation of one leveling mechanism 4 on the operation of other leveling mechanisms 4 can be suppressed as much as possible. As a result, the leveling can be achieved as accurately and well-balanced as possible without destroying the convergence of the leveling control. By suppressing hunting in the leveling control, the leveling control can be completed more quickly as a result.

[0146] In addition, in the present embodiment, it is possible to further perform a control that can further improve the performance of the leveling control. The controller 100 involved in the present embodiment is configured such that when the control mode composed of the first step and the second step is referred to as the "second mode", the control mode executed before the second mode, namely the "first mode", and the control mode executed after the second mode, namely the "third mode", are performed.

[0147] The names of these control modes are set according to the order of the modes, not according to their importance. For example, the first mode and the third mode may be omitted.

[0148] Hereinafter, the details of each control mode will be described in sequence.

[0149] (Details of leveling control)

[0150] Figure 5 2 is a flowchart showing an overview of the leveling control. As described above, the controller 100 executes the processing related to the leveling control in the order of the first mode, the second mode, and the third mode.

[0151] First, in step S1, the controller 100 performs settings such as connecting the cables 200 to each vibration isolation device 1. When performing this setting, the above-mentioned channel assignment process is performed. By performing the channel assignment process, 16 different IDs are assigned to the 16 displacement modules M1 to M4 constituting the active vibration isolation system S.

[0152] In the next step S2, the controller 100 executes the first mode of the leveling control. When performing the leveling control in the first mode, the controller 100 executes Figure 6 The third step is shown in step S11.

[0153] - Details of the first mode -

[0154] Figure 6 is a flowchart showing processing related to the first mode.

[0155] First, in Figure 6 Before step S11 , the controller 100 operates all the leveling mechanisms 4 to adjust the first displacements z1 at all the support positions P to outside the allowable range R1 (initial adjustment).

[0156] After that, the controller 100 causes all the leveling mechanisms 4 to work simultaneously in the direction of reducing the deviation from the allowable range R1. Specifically, in step S11, first, the controller 100 causes all the 16 leveling mechanisms 4 to work, and at each support position P, causes the lower end of each elastic body 3 to drop from a raised state until the first displacement z1 falls outside the allowable range R1, or causes the lower end of each elastic body 3 to rise from a lowered state until the first displacement z1 falls outside the allowable range R1. In this example, the latter configuration is adopted, but the former configuration may also be adopted depending on the processing content before step S11.

[0157] Furthermore, in step S11, the controller 100 determines whether the second displacement z2 is greater than or equal to a predetermined second threshold value T2 (z2 ≥ T2?) in all 16 channels based on the detection signal of the spring displacement sensor 6. If the determination is "No", the controller 100 causes the control program to enter step S12 to continue the operation of all the leveling mechanisms 4.

[0158] On the other hand, if the determination in step S11 is “Yes”, the controller 100 advances the control procedure to step S13. In step S13, the controller 100 determines whether the first displacement z1 exceeds the allowable range R1 for one or more channels.

[0159] When the lower end of each elastic body 3 is raised as described above, if the magnitude of the first displacement z1 exceeds the permissible range R1 (z1>T1+ΔT1), the judgment of step S13 is "yes". On the other hand, when the lower end of each elastic body 3 is lowered, if the magnitude of the first displacement z1 is less than the permissible range R1 (z1<T1-ΔT1), the judgment of step S13 is "yes".

[0160] When the determination in step S13 is "YES", the controller 100 causes the control routine to proceed to step S14, and changes the flag (Flag) indicating that the first mode has been completed from 0 to 1. Then, the control routine proceeds to step S15.

[0161] When the determination result in step S13 is “NO”, the controller 100 skips step S14 and proceeds the control procedure to step S15 while keeping the flag indicating that the first mode has been completed at 0.

[0162] In step S15, the controller 100 determines whether the flag is 1. If the determination is "yes", the controller 100 causes the control program to enter step S17. In this case, the controller 100 resets the second threshold value T2 to the initial value, completing the process. Figure 6 The control procedure shown.

[0163] On the other hand, if the determination result of step S15 is "No", the controller 100 causes the control program to proceed to step S16. In step S16, the controller 100 changes the second threshold value T2 and causes the control program to return to step S11. That is, until the determination result of step S13 becomes "Yes", the controller 100 causes all the leveling mechanisms 4 to continue to operate while changing the second threshold value T2.

[0164] Inability to escape Figure 6 In the case of the loop shown (even if the second threshold value T2 is repeatedly changed, the judgment of step S13 cannot become "yes"), it is also possible to forcibly end Figure 6 The control procedure shown.

[0165] when Figure 6 When the control program involved is completed, the controller 100 causes the control program to start from Figure 5 The process of step S2 proceeds to step S3. In step S3, the controller 100 performs the leveling control in the second mode.

[0166] - Details of the second mode -

[0167] Figure 7 is a flowchart showing the processing related to the second mode. Figure 8 This is a flowchart showing the leveling process common to the second mode and the third mode.

[0168] First, in Figure 7 In step S21, the controller 100 determines the magnitude relationship of the second displacement z2 between the four elastic bodies 3 for each of the four vibration isolation devices 1 (bases). This determination can be performed based on the detection signal of the spring displacement sensor 6 by selecting the displacement module with the largest second displacement z2 and the displacement module with the smallest second displacement z2 from the four displacement modules M1 to M4.

[0169] Likewise, in step S21 , the controller 100 calculates the difference between the maximum value and the minimum value of the second displacement z2 for each of the four vibration isolation devices 1 , thereby obtaining the same number of differences as the number of vibration isolation devices 1 .

[0170] Then, also in step S21, the controller 100 determines whether the four calculated differences fall within the predetermined ranges. This determination is performed for each of the four vibration isolation devices 1. Here, if the determination is "yes" in a certain vibration isolation device 1, it is determined that each elastic body 3 in the vibration isolation device 1 is flexed in a well-balanced manner (the degree of flexure is the same). In this case, the controller 100 determines that it is not necessary to eliminate the flexure difference, and the control program enters step S22.

[0171] On the other hand, if the determination in step S21 is “NO”, the controller 100 determines that the difference is equal to or greater than a predetermined value. In this case, the controller 100 executes a deflection difference elimination process to operate each leveling mechanism 4 so as to reduce the difference.

[0172] Specifically, when the determination result in step S21 is "No" in a certain vibration isolation device 1, it is determined that: in the vibration isolation device 1, each elastic body 3 is not bent in a well-balanced manner (the bending amount of each elastic body 3 is greatly different). Therefore, the controller 100 causes the control program to enter step S23 in order to eliminate the bending of the elastic body 3.

[0173] In step S23 , the controller 100 executes the deflection difference elimination process for the vibration isolation device 1 determined to need to eliminate the deflection of the elastic body 3 .

[0174] The details of step S23 are as follows: Fig.11 First, in step S231, the controller 100 reads the channels corresponding to the maximum and minimum values ​​of the second displacement z2.

[0175] In the next step S232, the controller 100 makes the corresponding leveling mechanism 4 work in the direction of reducing the second displacement z2 for the channel where the second displacement z2 becomes the maximum value. At the same time, the controller 100 makes the corresponding leveling mechanism 4 work in the direction of increasing the second displacement z2 for the channel where the second displacement z2 becomes the minimum value.

[0176] As shown in the next step S233, the process of step S232 is performed until the difference between the maximum value and the minimum value falls within the prescribed range.

[0177] Although not shown in the figure, in steps S231 to S233, the controller 100 also determines whether the first displacement z1 falls within the allowable range R1 for the channel whose second displacement z2 has reached the maximum value or the minimum value. The controller 100 does not allow the leveling mechanism 4 to operate for the channel whose first displacement z1 falls within the allowable range R1; the controller 100 allows the leveling mechanism 4 to operate only for the channel whose first displacement z1 does not fall within the allowable range R1.

[0178] When the first displacement z1 falls within the allowable range R1 in two channels where the second displacement z2 has reached the maximum value or the minimum value, the controller 100 may skip step S232 and return.

[0179] If the judgment in step S21 is "yes", the controller 100 performs a leveling process (step S22). The process includes the first step and the second step. The details of step S22 are as follows: Figure 8 It should be noted that, as shown in the chronological relationship between step S22, step S21 and step S23, the controller 100 according to the present embodiment performs the bending difference elimination process with priority over the leveling control (particularly the leveling control in the second mode).

[0180] First, in Figure 8 In step S101, the controller 100 reads detection signals of various sensors. The detection signals read here include detection signals of each platform displacement sensor 5.

[0181] In the next step S102, the controller 100 executes the first step. The controller 100 determines the channel corresponding to the support position P where the deviation D1 between the first displacement z1 and the allowable range R1 is the largest among all the channels of the active vibration isolation system S. The leveling mechanism 4 linked to the channel is also determined. It should be noted that, as described above, the deviation D1 here can be calculated using the first threshold value T1 (D1 = |T1-z1|).

[0182] In order to make the description clear, the channel determined in step S102 is also referred to as a specific channel (specific Ch). For example, when the deviation D1 is the largest in the third displacement module M3 of the second base 1B, Figure 4 The "chB3" in the above description becomes a specific channel. The leveling mechanism 4 linked to the specific channel is also referred to as a specific leveling mechanism 4.

[0183] In addition, two channels adjacent to a specific channel on the setting surface F (in other words, adjacent on the XY plane) are also referred to as adjacent channels (adjacent Ch). For example, as described above, when "chB3" is set as a specific channel, the controller 100 selects Figure 4"chB2" and "chB4" in the figure are regarded as two adjacent channels. The leveling mechanisms 4 linked to these adjacent channels are also respectively referred to as adjacent leveling mechanisms 4. Both adjacent leveling mechanisms 4 are adjacent to the specific leveling mechanism 4 on the setting surface F. Information indicating which mechanism is adjacent to which mechanism is set in advance and then read appropriately by the controller 100.

[0184] The adjacent frequency channel is selected from the frequency channels belonging to the same vibration isolation device 1 as the specific frequency channel determined in the first step. The specific leveling mechanism 4 and the adjacent leveling mechanism 4 are also the same.

[0185] In step S103 after step S102, the controller 100 determines whether the prescribed instruction cycle has passed. If the judgment is "yes", the controller 100 causes the control program to enter step S104. If the judgment is "no", the controller 100 causes the control program to enter step S108. The "instruction cycle" mentioned here refers to the output interval of the working instruction from the controller 100. The "working instruction" mentioned here refers to the electrical signal output from the controller 100 and input to each electric motor 45, especially the signal for starting each electric motor 45 to work. It should be noted that the judgment of step S103 can also be omitted.

[0186] In step S104 after step S103, processing related to the second step is performed. Specifically, the controller 100 selects two adjacent leveling mechanisms 4, 4 corresponding to the specific leveling mechanism 4. The controller 100 also calculates the difference of the first displacement z1 between the two adjacent leveling mechanisms 4, 4.

[0187] Here, the "difference" in step S104 refers to the difference in the first displacement z1 at the support position P corresponding to each channel. If the first displacements of two adjacent channels are z1' and z1", and the difference here is Da, the controller 100 performs a calculation equivalent to D = |z1'-z1"|.

[0188] Then, in steps S105 and S106 , the controller 100 executes a second step of operating the specific leveling mechanism 4 so as to reduce the deviation D1 involved in the specific channel.

[0189] When performing the second step, the controller 100 determines whether the difference Da obtained as described above is greater than or equal to a predetermined third threshold value (step S104). If the determination in step S104 is "No" (if the difference Da is less than a predetermined value), the controller 100 causes the control program to proceed to step S106. In step S106, the controller 100 operates only a specific leveling mechanism 4 among a total of 16 leveling mechanisms 4. In this case, the controller 100 inputs an operation command only to the electric motor 45 of the specific leveling mechanism 4.

[0190] On the other hand, when the judgment of step S104 is "yes" (when the difference Da is greater than the specified value), the controller 100 causes the control program to enter step S105. In step S105, the controller 100 causes a specific leveling mechanism 4 and one of two adjacent leveling mechanisms 4 among a total of 16 leveling mechanisms 4 to operate simultaneously (together) (electric motor 45: operate). Here, it is possible to make one adjacent leveling mechanism 4 a leveling mechanism whose value of the first displacement z1 is close to the value of the first displacement z1 of the specific leveling mechanism 4. In this case, the electric motor 45 of the other adjacent leveling mechanism 4 is not operated (electric motor 45: not operated). In this case, the controller 100 inputs an operation instruction to the electric motor 45 of the specific leveling mechanism 4 and the electric motor 45 of the adjacent leveling mechanism 4 that is the object of operation.

[0191] It should be noted that if a plurality of leveling mechanisms 4 are operated simultaneously as described above, seeking may occur. However, in the present embodiment, since specific leveling mechanisms 4 are operated one after another, the occurrence of seeking is suppressed compared to a configuration in which randomly selected leveling mechanisms 4 are operated simultaneously.

[0192] Although the adjacent leveling mechanism 4 and the specific leveling mechanism 4 are operated simultaneously, the leveling mechanism 4 located at non-adjacent positions (eg diagonal positions) is not operated simultaneously in each vibration isolating device 1. This is also effective in suppressing the occurrence of seeking.

[0193] In the next step S107, the electric motor 45 to which the operation command is input in step S105 or step S106 operates within a prescribed minimum operation time. The shortest operation time is set to a time shorter than the command cycle. At this time, the controller 100 may also stop the operation of the electric motor 45 by inputting a stop command to the electric motor 45 after the shortest operation time. The "stop command" referred to here refers to an electrical signal output from the controller 100 and input to each motor 45, in particular, a signal for stopping the operation of each electric motor 45.

[0194] That is, the controller 100 according to the present embodiment operates each electric motor 45 constituting a specific leveling mechanism 4 or an adjacent leveling mechanism 4 at the shortest operation time interval, for example, multiple times. Instead of continuously operating until the first displacement z1 falls within the allowable range R1 (one operation opportunity), the motor 45 operates multiple times and little by little, so that each channel can gradually approach the allowable range R1 without deviation. This is advantageous in suppressing the stroke of the elastic body 3.

[0195] Then, the controller 100 causes the control procedure to proceed from step S107 to step S108. In step S108, the controller 100 determines whether the current control mode is the second mode.

[0196] If the determination result in step S108 is “Yes”, the controller 100 ends the Figure 8 In this case, the controller 100 makes the control program from Figure 7 Step S22 proceeds to step S24.

[0197] In step S24, the controller 100 determines whether the ratio of the channels (leveling mechanisms 4) whose first displacement z1 falls within the allowable range R1 among the total 16 channels (leveling mechanisms 4) is greater than a prescribed ratio. The prescribed ratio is a parameter set in advance. The prescribed ratio is preferably greater than 60% and less than 90%, and more preferably greater than 70% and less than 80%. The value of the prescribed ratio can be changed based on manual input or automatic processing.

[0198] More specifically, in step S24, the controller 100 determines whether the first displacement z1 in each of the 16 channels is within the allowable range R1 (T1-ΔT1≤z1≤T1+ΔT1). Based on the determination result, the controller 100 performs determination related to the predetermined ratio.

[0199] It should be noted that Figure 7 The process is only an example. The processing involved in step S24 can be moved to the time before step S21, or can be moved to the time between step S21 and step S22. In this case, the judgment of whether the first displacement z1 falls within the allowable range R1 (T1-ΔT1≤z1≤T1+ΔT1) can be used in the judgment of step S102. Fig. 9 The processes involved are also the same.

[0200] In this embodiment, the predetermined ratio is set to 75%. In this case, the judgment in step S24 is "yes" when there are 12 or more channels (leveling mechanisms 4) whose first displacement z1 falls within the allowable range R1, and "no" when there are less than 11 channels.

[0201] If the determination in step S24 is "NO", the controller 100 returns the control routine to step S21. Since the deflection of the elastic body 3 is assumed to change by the leveling process (particularly the second step), the control routine returns to the determination in step S21 and the process in step S23.

[0202] On the other hand, if the determination in step S24 is "Yes", the controller 100 ends Figure 7 In this case, the controller 100 changes the control program from Figure 5 The process of step S3 proceeds to step S4. In step S4, the controller 100 performs the leveling control in the third mode.

[0203] - Details of the third mode -

[0204] Fig. 9 is a flowchart showing the processing related to the third mode. Fig.10 is a flowchart showing the processing related to the third mode.

[0205] from Figure 7 and Fig. 9 It can be seen from the comparison that the processing involved in the third mode is the same as that of the second mode except for the judgment in step S34. Fig. 9 Step S31 and Figure 7 The step S21 is common to Fig. 9 Step S32 and Figure 7 The step S22 is common to Fig. 9 Step S33 and Figure 7 It should be noted that, as shown by the chronological relationship between step S32, step S31, and step S33, the controller 100 according to the present embodiment performs the bending difference elimination process with priority over the leveling control (particularly the leveling control in the third mode).

[0206] For example, in Fig. 9 In step S32, the controller 100 executes Figure 8 The control procedure shown. The processing related to a specific channel and adjacent channels is as described above.

[0207] As a major difference from the second mode, when performing leveling control in the third mode, the controller 100 Figure 8 The controller 100 makes the control procedure proceed to step S108 to execute the processing specific to the third mode (the processing specific to the third mode).

[0208] The details of the third mode inherent processing are as follows Fig.10 As shown, the controller 100 first stops all the electric motors 45 in step S109 (more generally, puts all the leveling mechanisms 4 in a non-operating state).

[0209] In the next step S110, the controller 100 determines whether a predetermined time has elapsed since all the electric motors 45 were stopped. If the determination is "NO", the control routine returns to step S109. The controller 110 continues step S109 until the predetermined time has elapsed.

[0210] That is, the controller 100 is configured to, when performing the leveling control in the third mode, perform the first step and the second step described above, Figure 8 After the second step is completed in steps S105 to S107, a step (fourth step) of waiting for a predetermined time in a state where all leveling mechanisms 4 have stopped is executed. The predetermined time mentioned here is a parameter set in advance. The predetermined time is preferably less than 4 seconds, and more preferably less than 2 seconds. The value of the predetermined time can be changed based on manual input or automatic processing.

[0211] On the other hand, if the determination in step S110 is "yes", the controller 100 ends Fig.10 In this case, the controller 100 changes the control program from Fig. 9 Step S32 proceeds to step S34.

[0212] In step S34 , the controller 100 determines whether the first displacement z1 falls within the allowable range R1 for all channels (leveling mechanisms 4 ).

[0213] If the determination in step S34 is "NO", the controller 100 returns the control routine to step S31. Since the deflection of the elastic body 3 is assumed to change by the leveling process (particularly the second step), the control routine returns to the determination in step S31 and the process in step S33.

[0214] On the other hand, if the determination in step S34 is "Yes", the controller 100 ends Fig. 9 In this case, the controller 100 changes the control program from Figure 5 The process proceeds from step S4 to step S5. In step S5, the controller 100 activates the vibration isolation device 1. By the activation, each vibration isolation device 1 becomes capable of executing active vibration isolation control.

[0215] (Summarize)

[0216] As described above, according to this embodiment, as shown in FIG. Figure 8 As described above, by operating each leveling mechanism 4 in sequence, the influence of the operation of one leveling mechanism 4 on the operation of other leveling mechanisms 4 can be suppressed as much as possible. As a result, it is possible to achieve the most accurate and well-balanced leveling without destroying the convergence of the leveling control. By suppressing the seeking in the leveling control, as a result, the leveling control can also be completed more quickly.

[0217] As reference Figures 5 to 8As described above, the leveling control in the first mode is executed when relatively rough control can be tolerated, such as immediately after the start of the leveling control, and thereafter, the leveling control in the second mode is executed when a predetermined accuracy or higher is required.

[0218] In this way, by distinguishing the control modes to be used according to the progress of the leveling control, the leveling can be performed as quickly as possible and as accurately as possible. As a result, the performance of the leveling control is significantly improved.

[0219] The active vibration isolation system S involved in this embodiment can contribute to achieving the international goal of creating a sustainable and better world by 2030 as recorded in the "Sustainable Development Goals 2030 Agenda" unanimously adopted by the member states at the United Nations Summit in September 2015, that is, Goal 9 of the Sustainable Development Goals (SDGs: Sustainable Development Goals) "Building a foundation for industrial and technological innovation."

[0220] As reference Figure 5 and Figure 7 to Figure 10 As described, the leveling control in the second mode is performed in the middle stage of the leveling control, and the leveling control in the third mode is performed in the final stage of the leveling control. By performing the third mode, the influence of the inertial force accompanying the operation of each leveling mechanism 4 can be suppressed as much as possible. The third mode provides more accurate leveling than the second mode.

[0221] For example, consider a situation where each leveling mechanism 4 is composed of electric motors 45 as described above, and a stop command is input to any one of the electric motors 45. In this case, the motor to which the stop command is input continues to rotate under the action of inertia for a very short period of time (about several hundred milliseconds in the case of this embodiment) after the input.

[0222] In this case, even if the first displacement z1 falls within the allowable range R1 at any supporting position P when the stop command is input to the specified electric motor 45, the first displacement z1 may be affected by the rotation caused by the inertial force and run out of the allowable range R1. This possibility can be conceived not only for the supporting position P that is the input object of the stop command, but also for other supporting positions P adjacent to it. On the contrary, even if the first displacement z1 at any supporting position P runs out of the allowable range R1, the first displacement z1 may be affected by the rotation caused by the inertial force and accidentally fall into the allowable range R1. These possibilities are more significant when the load distribution of the support 300 is uneven than when it is evenly distributed. In response to this problem, by performing leveling control in the third mode as in the present embodiment, the influence of the inertial force as described above can be suppressed as much as possible.

[0223] In this way, by selecting and using the control mode according to the progress of the leveling control, it is possible to achieve both the relatively rapid leveling of the second mode and the relatively accurate leveling of the third mode. As a result, the performance of the leveling control is significantly improved.

[0224] like Figure 7 As shown in step S24, by shifting from the second mode to the third mode based on the ratio of the leveling mechanism 4 satisfying the predetermined condition, it is possible to smoothly shift from the second mode to the third mode according to the progress of the leveling control.

[0225] As reference Figure 8 As described in steps S104 to S106, by configuring the adjacent leveling mechanism 4 to operate simultaneously in addition to the specific leveling mechanism 4, the stroke (displacement) of the elastic body 3 involved in the specific leveling mechanism 4 can be suppressed. In each active vibration isolation device 1, the deflection difference between the elastic bodies can be suppressed.

[0226] By operating adjacent leveling mechanisms 4 simultaneously instead of operating the diagonally located leveling mechanisms 4 simultaneously, the influence of one leveling mechanism 4 on the operation of other leveling mechanisms 4 can be suppressed to a minimum. This is particularly effective for the vibration isolation device 1 having a substantially square upper plate 13.

[0227] In addition, if Figure 7 As shown in step S21 and step S23, by performing control based on the second displacement z2, the deflection difference of each elastic body 3 can be suppressed. Suppression of the deflection difference is useful in achieving well-balanced leveling corresponding to the load distribution of the load 300 and ensuring the durability of each elastic body 3.

[0228] - Explanation of symbols -

[0229] S Active Vibration Isolation System

[0230] F Installation surface (specified surface)

[0231] P Support position

[0232] 1 Active vibration isolation device

[0233] 3 Elastomer

[0234] 4 Leveling mechanism

[0235] 42 Spring seat

[0236] 5 Platform displacement sensor

[0237] 6 Spring displacement sensor

[0238] 13 Upper board (platform)

[0239] 100 Controller

[0240] 300 Load (supported object)

[0241] z1 first displacement

[0242] z1 Second displacement

[0243] T1 First Threshold

[0244] D1 deviation.

Claims

1. An active vibration isolation system, comprising one or more active vibration isolation devices arranged on a predetermined surface, and a controller for controlling the one or more active vibration isolation devices respectively, wherein the active vibration isolation system supports a supported object from below through the one or more active vibration isolation devices, characterized in that: The one or more active vibration isolation devices include a platform, a plurality of elastic bodies, a plurality of leveling mechanisms, and a plurality of platform displacement sensors. The platform is used to place the supported object. The plurality of elastic bodies are arranged at a plurality of mutually different supporting positions, and elastically support the platform from below at each of the supporting positions. The plurality of leveling mechanisms are arranged in a manner corresponding to the plurality of elastic bodies, respectively, support the corresponding elastic bodies from below, and displace the platform in the up-down direction via the elastic bodies. The plurality of platform displacement sensors are arranged to correspond to the plurality of elastic bodies, respectively, and detect a first displacement indicating a displacement of the platform at each of the support positions relative to the predetermined surface. The controller performs leveling control before the active vibration isolation system is started. The leveling control makes the multiple leveling mechanisms work in sequence based on the detection signals of the multiple platform displacement sensors so as to make the first displacements fall within a prescribed allowable range respectively. The controller repeatedly executes the first step and the second step when performing the leveling control. The first step determines a leveling mechanism among the plurality of leveling mechanisms, which corresponds to a support position where a deviation between the first displacement and the allowable range is the largest. The second step operates the leveling mechanism determined according to the first step so as to reduce the deviation.

2. The active vibration isolation system according to claim 1, characterized in that: The controller is configured to execute the leveling control in a predetermined first mode before executing the leveling control in a second mode consisting of the first step and the second step. When the controller performs the leveling control in the first mode, After the first displacements of all the support positions are adjusted to outside the allowable range by operating all of the plurality of leveling mechanisms, a third step of operating all of the plurality of leveling mechanisms simultaneously is performed to reduce the deviation from the allowable range.

3. The active vibration isolation system according to claim 1, characterized in that: The controller is configured to: after executing the leveling control in the second mode consisting of the first step and the second step, execute the leveling control in a predetermined third mode; When the controller performs the leveling control in the third mode, the controller repeatedly executes the first step, the second step and the fourth step, The fourth step returns to the state before the first step after the second step is completed, and all the plurality of leveling mechanisms are placed in a non-operating state, and then wait for a predetermined time.

4. The active vibration isolation system according to claim 3, characterized in that: The controller shifts from the second mode to the third mode when a ratio of the leveling mechanisms whose first displacement falls within the allowable range among the plurality of leveling mechanisms is greater than a predetermined ratio.

5. The active vibration isolation system according to claim 1 or 3, characterized in that: If the leveling mechanism determined in the first step is taken as a specific leveling mechanism, two leveling mechanisms adjacent to the specific leveling mechanism on the specified surface are taken as adjacent leveling mechanisms, respectively. The controller calculates the difference of the first displacement between two adjacent leveling mechanisms. When performing the second step, When the difference is smaller than a specified value, the controller operates only the specific leveling mechanism. On the other hand, when the difference is greater than the specified value, the controller operates one of the two adjacent leveling mechanisms whose first displacement value is close to the first displacement value of the specific leveling mechanism together with the specific leveling mechanism.

6. The active vibration isolation system according to claim 1, characterized in that: The one or more active vibration isolation devices further include a plurality of spring seats and spring displacement sensors, respectively. The plurality of spring seats are respectively arranged in the plurality of leveling mechanisms to support the elastic body respectively. The spring displacement sensor is arranged to correspond to each of the plurality of elastic bodies, and detects a second displacement indicating a displacement of the spring seat at each supporting position relative to the predetermined surface. The controller determines the magnitude relationship of the second displacement between the plurality of elastic bodies for each of the active vibration isolation devices, and when the difference of the second displacement is greater than a predetermined value, executes a deflection difference elimination process to operate each of the leveling mechanisms so as to reduce the difference. The controller performs the deflection difference elimination process with priority over the leveling control.

7. A leveling method for an active vibration isolation system, the active vibration isolation system comprising one or more active vibration isolation devices arranged on a predetermined surface, and a controller for controlling the one or more active vibration isolation devices respectively, the active vibration isolation system supporting a supported object from below by using the one or more active vibration isolation devices, The one or more active vibration isolation devices respectively include a platform, a plurality of elastic bodies, a plurality of leveling mechanisms and a plurality of platform displacement sensors, The platform is used to place the supported object. The plurality of elastic bodies are arranged at a plurality of mutually different supporting positions, and elastically support the platform from below at each supporting position. The plurality of leveling mechanisms are arranged in a manner corresponding to the plurality of elastic bodies, respectively, support the corresponding elastic bodies from below, and displace the platform in the up-down direction via the elastic bodies. The plurality of platform displacement sensors are arranged to correspond to the plurality of elastic bodies, respectively, and detect a first displacement indicating a displacement of the platform at each of the support positions relative to the predetermined surface. The controller performs leveling control before the active vibration isolation system is started. The leveling control makes the multiple leveling mechanisms work in sequence based on the detection signals of the multiple platform displacement sensors so as to make the first displacements fall within a prescribed allowable range respectively. The controller repeatedly executes the first step and the second step when performing the leveling control. The first step determines a leveling mechanism among the plurality of leveling mechanisms, which corresponds to a support position where a deviation between the first displacement and the allowable range is the largest. The second step operates the leveling mechanism determined according to the first step so as to reduce the deviation.

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