JPH044337A - Active vibration damping device - Google Patents

Abstract

PURPOSE:To obtain the constitution being compact in the whole by installing a shifting means for position-controlling a supporting frame body in a specific direction according to the detection value, between a supporting frame body and a base board, and reducing the cut-off frequency. CONSTITUTION:A payload 10 is supported in noncontact form in the three-axis direction on a supporting frame body 18 by the electro-magnetic suspensions 15 - 17. The external turbulence applied on the payload 10 is detected by shift sensors 12 - 14, and the exciting current of a controller 20 is controlled on the basis of the information. Through this control, each supporting force of the electromagnetic suspensions 15 - 17 is adjusted so that vibration is eliminated, and the transmission of the external turbulence is cut off. When a basic board 11 is shifted by receiving a large external turbulence, a screw rod 30 is revolution-operated, and the supporting frame body 18 is shifted so as to always keep a neutral position for the payload 10. Accordingly, the external turbulence in the Z-axis direction is treated by the quantity in addition of the allowable shift of the electromagnetic suspension and the stroke of a shifting means 19, and also the external turbulence in the low frequency region having the large shift quantity can be disposed of.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an active vibration damping device that performs support and vibration isolation using magnetic force.

[Prior Art] The present applicant has previously developed a system for properly supporting experimental equipment (payloads) used in microgravity environments such as outer space ([Vibration isolation and support mechanism for equipment in space]) that isolates disturbances and appropriately supports experimental equipment (payloads). ”, Japanese Patent Application No. 61165011, etc.).

As shown in FIG. 5, this system includes a support frame 3 that supports a payload 1 by a voice coil electromagnetic suspension 2, a sensor 4 that detects disturbances acting on the payload 1 as acceleration or displacement, and a sensor 4 that detects disturbances acting on the payload 1 as acceleration or displacement. The control section 5 controls the excitation current supplied to the electromagnetic suspension 2 based on the output signal of the electromagnetic suspension 2.

As shown in FIG. 6, the electromagnetic suspension 2 consists of a permanent magnet 6 attached to the payload 1 and a coil 7 facing the permanent magnet 6 at a predetermined distance, and is arranged in three axes of rectangular coordinates. (The direction perpendicular to the plane of the paper is omitted in FIG. 5). The payload 1 is supported by the magnetic force without contact, and the supporting force is constant regardless of displacement if the excitation current is constant, and by appropriately controlling the current value, vibration of the support frame 3 is (disturbance) is prevented from being transmitted to payload 1.

This system can block disturbances that degrade the microgravity environment in aircraft, rockets, space shuttles, etc., and provides an excellent environment for conducting μ-g experiments.

[Problems to be Solved by the Invention] In this system, as shown in the Bode diagram in FIG. 7, the state of disturbance interruption is expressed as the ratio of payload acceleration p to disturbance acceleration q (p/q>). The set cutoff frequency f. Actively acts on disturbances in the following frequency range,
This reduces the ratio value.

In other words, the cutoff frequency f. Position control is performed for low-frequency vibration disturbances smaller than (see Fig. 8A) (see Fig. 8B), and is blocked for large high-frequency vibrations (see Fig. 9A) (see Fig. 8B). (see Figure 9B). That is, the cutoff frequency f.

The smaller the value, the more completely vibrations can be blocked over a wider frequency range.

However, the cutoff frequency f. and electromagnetic suspension 2
There is a relationship between the allowable displacement δ and the disturbance acceleration q as shown in the following equation.

fo −1/2π×F]1...■Therefore, the cutoff frequency f. If an attempt is made to reduce the allowable displacement δ, the allowable displacement δ increases, and even when the disturbance acceleration q is large, the allowable displacement δ inevitably increases accordingly. Therefore, when the disturbance is large, the cutoff frequency f. If .delta. is made small, there is a problem that the system becomes a long system having an electromagnetic suspension 2 with a large allowable displacement .delta..

For example, taking the μmg environment caused by an aircraft as an example, there is an acceleration disturbance of up to 1O-2G order in the worst case, and the cutoff frequency f is 0.1H7. If you try to set this, you will need an allowable displacement of ±25 cm. μ
In the case of -g experiments, it is necessary to make the mounted equipment as compact as possible, so a system that requires such a large stroke is not realistic.

In view of the above circumstances, the present invention was devised in order to provide an active vibration damping device that can reduce the cutoff frequency even when the disturbance acceleration is large and can be made compact as a whole.

[Means for Solving the Problems] The present invention includes a rectangular disturbance detection means for detecting disturbance of a supported object provided on a base, and an electromagnetic device in which an excitation current is controlled based on a detected value by the disturbance detection means. A suspension, a support frame that supports the supported object in three orthogonal axes directions via the electromagnetic suspension, and a system that controls the position of the support frame in a specific direction based on the detected value, which is provided between the support frame and the base. It is equipped with means of transportation.

[Function] With the above configuration, the support frame supports the supported object in a non-contact manner by the magnetic force of the electromagnetic suspension, and also transmits disturbance by controlling the excitation current based on the detected value of the disturbance detection means. is blocked.

The moving means moves the support frame to follow a large acceleration disturbance in a specific direction, thereby responding to the permissible displacement of the electromagnetic suspension and ensuring a disturbance blocking effect.

"Example" Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of an active vibration damping device according to the present invention, and show a case where it is mounted on an aircraft via a base 11. FIG.

This active vibration damping device includes a displacement sensor 12 which is a disturbance detection means for detecting disturbance to a payload 10 which is a supported body.
, 13.14, and conventional electromagnetic suspensions 15, 16.17 in which the excitation current is controlled based on the detected values.
, a support frame 18 that supports the payload 1o in the orthogonal axis directions (X, Y, Z) via electromagnetic suspensions 15...17, and a detection value provided between the support frame 18 and the base 11. It mainly consists of one moving means for controlling the position of the support frame 18 in a specific direction, and further includes a controller 20 connected to the displacement sensors 12...14, electromagnetic suspensions 15...17, and the moving means 19. ing.

The base 11 includes a bottom plate 21 that is placed on the aircraft body, and a bottom plate 21 that is placed on the aircraft body.
and a side plate 22 bent at right angles, and is formed into an L-shape so as to surround the side surfaces of the payload 10 in the Z and X directions.

The support frame 18 has a cubic structure that surrounds the payload 10 inside the base 11, and has a sap member 23 with a cross-sectional shape forming each side, and one sap member on each surface in a predetermined direction. A total of six strips 24 are provided between the sapwoods 23 to form appropriate hooks. Two displacement sensors 12...14 and two electromagnetic suspensions 15...17 are attached to each of these strip plates 24. In addition, in FIG. 1, only each axis-set is shown.

In this embodiment, as shown in FIG. 3, these six displacement sensors 12...14 and electromagnetic suspensions 15...17 measure the relative displacement along the three axes and the respective It detects rotational displacement around the axis and performs six degrees of freedom control.

For example, the displacement sensor 12 provided on the X-axis side detects the amount of displacement x, x2 along the X-axis, and this detected value is sent to the 6 and the arithmetic processing units 27 and 28 of the circuits 25 and 26 input these displacement amounts X 1+
2 to calculate the amount of rotational displacement θy around the Y-axis, and based on these detected and calculated values, the excitation current of the corresponding electromagnetic suspension 15 is outputted as appropriate.

In this embodiment, one moving means moves in the vertical direction of the aircraft (
X direction). As shown in Figure 4, in the μ-g environment caused by an aircraft, the disturbance acceleration in the vertical direction of the aircraft (shown in A) is greater than the disturbance acceleration in the longitudinal direction of the aircraft and the horizontal direction (B, C) of the aircraft. -Due to orders of magnitude larger.

That is, in order to cope with a disturbance acceleration that is particularly larger than other directions, a specific direction (position control direction) of one moving means is set.

As shown in FIG. 2, one moving means has a threaded rod 30 attached to the side plate 22 of the base 11 via two flanges, and is screwed into the threaded rod 30 with a hole screw and faces the side plate 22. The nut body 31 is attached to the strip plate 24 of the support frame 18, and the servo motor 32 is connected to a threaded rod 30. The rotation speed, rotation direction, and operating time of the servo motor 32 are adjusted by the controller 20. That is, based on the detected value in the Z-axis direction, the support frame 1
The position of 8 is controlled.

Further, as shown in FIG. 1, the side plate 22 has a threaded rod 3.
A guide rail 33 is attached to the support frame 18 and extends parallel to the guide rail 33, and a leg block 34 is attached to the support frame 18. That is, the threaded rod 30
The movement of the support frame 18 is stably guided.

Next, the operation of this embodiment will be explained.

Under the μ-g environment of the aircraft, the payload 10 is supported by the electromagnetic suspensions 15 . . . 17 on the support frame 18 in three axial directions without contact. Disturbances to the payload 10 are detected by the displacement sensors 12...14, and the excitation current of the control roller 20 is controlled based on the information. With this control, the electromagnetic suspension 1
The supporting forces of Nos. 5 to 17 are adjusted to eliminate vibrations, and transmission of external disturbances is blocked.

In particular, for disturbances in the Z-axis direction that are larger than disturbances in other directions, the position of the moving means 19 or the support frame 18 is controlled. That is, if the base 11 moves due to a large disturbance, the relative position between the support frame 18 and the payload 10 will change and exceed the permissible displacement δ of the electromagnetic suspension 17, creating a risk of contact. On the other hand, as the threaded rod 30 rotates to follow the displacement, the support frame 18 moves so as to be always maintained at a neutral position with respect to the payload 10. As a result, disturbances in the Z-axis direction are responded to by the sum of the permissible displacement δ of the electromagnetic suspension and the stroke of the moving means 19, which is sufficient even for disturbances in the low frequency range with large displacements. I can handle it.

In this way, the payload 10 is supported without contact by the support frame 18 to which the electromagnetic suspensions 15 . Since it is supported, the cutoff frequency f is small.

Even if set, collisions and the like can be prevented by controlling the position of one moving means, and disturbances can be blocked over a wide frequency range.

In other words, the electromagnetic suspensions 15...17 do not need to have a large allowable displacement δ, and the size of the active vibration damping device can be made compact. For example 0.
When dealing with a disturbance of about 0.02G, even if the allowable displacement of the electromagnetic suspensions 15...17 is set to ±51, if the stroke of the threaded rod 30 is set to ±10On+n+,
The cutoff frequency f is about 0.511□.

can be set.

In this embodiment, a displacement sensor is shown as the disturbance detection means, but an acceleration sensor may be provided and connected to the controller.

In this case, for example, as shown in FIG. 1, an acceleration sensor S may be provided at the center of gravity of the payload to detect the direction and magnitude of the acceleration.

Further, the present invention can be applied not only to a μmg environment caused by an aircraft, but also to a μmg environment caused by a space shuttle or a rocket.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects are achieved.

Disturbance detecting means for detecting disturbance of a supported object, an electromagnetic suspension whose excitation current is controlled based on the detected value, a support frame body that supports the supported object via the electromagnetic suspension, and a support frame body that supports the supported object via the electromagnetic suspension. Since it is equipped with a moving means that controls the position of the body, even when disturbance acceleration is large, the cutoff frequency of the electromagnetic suspension can be reduced by controlling the position in that direction using the moving means and the allowable displacement of the electromagnetic suspension. Moreover, the entire device can be made compact.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the active vibration damping device according to the present invention, FIG. 2 is a sectional view of the main part thereof, and FIG. 3 is a control diagram for explaining the control of the electromagnetic suspension shown in FIG. 1. circuit diagram,
Figure 4 is a frequency distribution diagram showing the disturbance acceleration in the three orthogonal axes directions in Figure 1, and Figure 5 is a diagram showing the distribution of disturbance acceleration in the three orthogonal axes directions in Figure 1.
A configuration diagram showing the support mechanism, FIG. 6 is a side sectional view showing the electromagnetic suspension, FIG. 7 is a Bode diagram for explaining the characteristics of the electromagnetic suspension, and FIG. 8 is for explaining the action of the electromagnetic suspension. Fig. 9 is a time change diagram (A) of support frame acceleration under low frequency vibration and a time change diagram (B) of payload acceleration under low frequency vibration. It is a change diagram (B). In the figure, 10 is a payload as a supported body, 11 is a base, 1
2, 13. 14 is a displacement sensor serving as a disturbance detection means; 15;
16.17 is an electromagnetic suspension, 18 is a support frame, 1
9 is a means of transportation. Patent applicant: Ishikawajima Harima Heavy Industries Co., Ltd. Ishikawajima Soundproofing Industry Co., Ltd. Representative patent attorney: Nobuo Kinutani (1 other person) dB Figure

Claims (1)

[Claims] 1. Disturbance detection means for detecting disturbance of the supported object provided on the base, an electromagnetic suspension whose excitation current is controlled based on the detected value by the disturbance detection means, and A support frame that supports the support in three orthogonal axes, and a moving means that is provided between the support frame and the base and controls the position of the support frame in a specific direction based on the detected value. An active vibration damping device characterized by: