JP4078712B2 - Payload anti-vibration device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a payload anti-vibration device that protects a payload mounted on a launch rocket from vibration and impact, and more particularly to an anti-vibration device that can improve clearance performance and reduce clearance loss.
[0002]
[Prior art]
A payload such as an artificial satellite is mounted at the tip of a launch vehicle, but conventionally the payload is fixed at the tip of the launch vehicle, and vibrations caused by the engine generated in the rocket and air friction of the fairing are directly affected. It is not preferable because it is transmitted to the payload.
[0003]
In order to block vibration, it is conceivable that rubber is interposed on the entire bottom surface of the payload. This prevents the payload from receiving significant vibrations from the rocket. However, since the satellite that becomes the payload is, for example, 2 m in diameter and 7 m in height and high in height compared to the size of the bottom surface, if it is supported only on the bottom surface, it is supported at one point, and the tip of the payload tends to swing. There is a problem that. In addition, the amplitude of the tip of the payload increases even at a slight swing angle, and the tip of the payload may contact and collide with the inner wall of the rocket fairing.
[0004]
The present applicant has previously proposed a vibration isolator provided with a plurality of elastic support members that are inclined at a predetermined inclination angle with respect to the propulsion shaft around the tip of the launch rocket and elastically support the payload. (Japanese Patent Application No. 10-111975).
[0005]
As a result, the swing of the tip of the payload is eliminated, and the payload vibrates slightly in the direction along the propulsion axis (hereinafter referred to as the propulsion direction) or in the direction toward the propulsion axis (hereinafter referred to as the horizontal direction) while maintaining the standing posture. It will be.
[0006]
[Problems to be solved by the invention]
However, in a completely passive vibration isolator using the elastic support member, it is impossible to suppress vibration (resonance) near the natural frequency, and the amplitude at the resonance frequency becomes extremely large. Is inevitable. In the above vibration isolator, the payload can be maintained in an upright posture, but due to resonance, the payload vibrates in a propulsion direction or a horizontal direction rather than the vibration received from the rocket. Such a large vibration gives an impact (G) to the device mounted on the payload, or in the case of manned, it gives an impact to the crew, which is not preferable. Further, when the amplitude in the horizontal direction increases, the payload may come into contact with or collide with the inner wall of the fairing, and the clearance loss between the payload and the fairing increases.
[0007]
Therefore, an object of the present invention is to provide a vibration isolator capable of solving the above-described problems and reducing the clearance loss while improving the vibration isolation performance.
[0008]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a payload mounted on a tip of a launch rocket via a plurality of extendable support members, a sensor for detecting the displacement of the payload is provided, and based on this displacement Providing a control circuit for controlling the expansion and contraction characteristics of each of the support members so that the vibration of the payload is reduced , and arranging the support members to expand and contract in the direction along the propulsion shaft at least at three locations around the propulsion shaft, And it arrange | positions so that it may expand-contract in the direction which goes to a propulsion shaft at at least two places around a propulsion shaft, respectively .
[0010]
The support member may be composed of an actuator that expands and contracts by power, and the expansion and contraction motion of each actuator may be controlled by the control circuit.
[0011]
The support member is composed of a variable damping damper that exhibits resistance to expansion and contraction, and the damping of the resistance is controllable, and the payload is tilted around the tip of the launch rocket at a predetermined tilt angle with respect to the propulsion shaft. A plurality of elastic support members that are elastically supported may be provided, and the damping characteristic of each variable damping damper may be controlled by the control circuit.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
As shown in FIG. 1, a flat base 3 on which the vibration isolator of the present invention is placed and a fairing (not shown) that covers the payload 2 are provided at the tip of the launch rocket 1. The bottom surface of the payload 2 is fixed to a disk-shaped platform 4. The platform 4 has a flat surface facing the base 3, and a protrusion 4 a extending toward the base 3 is formed at a position overlapping the propulsion axis A at the center of the flat surface. The platform 4 is supported by five support members 5 provided on the base 3. Of these, three support members 5 a have a base end portion fixed to the base 3 and a tip end portion fixed to the platform 4. These three support members 5a are arranged at three locations around the propulsion shaft A, and are provided to stand up with respect to the base 3 so that each support member 5a expands and contracts in the direction along the propulsion shaft A. Further, the remaining two support members 5b are fixed to the protrusions 3a on the base 3 disposed at two places around the propelling shaft A, and the distal ends are fixed to the protrusions 4a. These two support members 5b are arranged so as to be inclined with respect to the base 3 so that the two support members 5b are orthogonal to each other and extend in the direction toward the respective propulsion axes A.
[0014]
The five support members 5 are composed of actuators that expand and contract by power, for example, hydraulic cylinders.
[0015]
On the base 3, a controller box 6 that houses a control circuit that controls the expansion and contraction motion of each actuator (support member) 5 and a power source 7 are provided. Although not shown, as a sensor for detecting the displacement amount of the payload 2, a position sensor for detecting a relative position between the platform 4 and the base 3 (a relative position between the payload 2 and the rocket 1), and an absolute value of the payload 2. And an acceleration sensor for detecting a target acceleration. The absolute velocity may be obtained by integrating the absolute acceleration.
[0016]
The control circuit accommodated in the controller box 6 controls the expansion / contraction motion of each actuator.
[0017]
The control block configuration of the control circuit is similar to the control block configuration of FIG. 3 to be described later, and the expansion / contraction motion of each actuator is controlled using the relative displacement amount and the absolute displacement amount of the payload 2. It has become.
[0018]
Another embodiment will be described.
[0019]
As shown in FIG. 2, the five support members 5 are composed of variable damping dampers. The variable damping damper has a cylinder and pores that allow fluid to flow in and out of the cylinder. The fluid in the cylinder exhibits resistance to expansion and contraction, and the resistance is attenuated by the fluid flow in the pores. ing. And the diameter of this pore is comprised so that adjustment is possible, and, thereby, damping force (damping rate) is controllable.
[0020]
In this embodiment, four elastic support members 8 that elastically support the payload are provided. These four elastic support members 8 are fixed to inclined support angle adjusting joints 3b on the base 3 disposed at four locations around the propulsion axis A, and the distal ends are fixed to the platform 4. These elastic support members 8 are each inclined at a predetermined inclination angle with respect to the propulsion axis A. The elastic support member 8 is made of silicon laminated rubber.
[0021]
In the four elastic support members 8, the payload 2 is expressed by a mathematical formula using the height of the center of gravity of the payload 2, the horizontal distance from the axis of the payload 2 to the elastic support member 8, the longitudinal and lateral rigidity of the elastic support member 8, and the like. The conditions under which no oscillation occurs are uniquely determined. From this condition, the inclination angle α of the elastic support member 8 with respect to the propulsion axis A is derived. At this time, the natural frequency in the propulsion direction and the natural frequency in the horizontal direction are also uniquely determined.
[0022]
The vibration isolator of FIG. 2 can be said to be a combination of a passive vibration isolator composed of four elastic support members 8 and a semi-active vibration isolator composed of five variable damping dampers 5.
[0023]
FIG. 3 is a control block diagram of the vibration isolator of FIG.
[0024]
This control block is a combination of a passive damper system and a skyhook damper system. First, the passive damper system corresponds to a passive vibration isolator composed of four elastic support members 8, and a relative displacement between the platform 4 and the base 3 is applied in accordance with the displacement of the body due to disturbance acceleration or the like. A damping force is obtained by multiplying the velocity obtained by differentiating the displacement by the passive damping ratio. On the other hand, the skyhook damper system corresponds to a quasi-active vibration isolator composed of five variable damping dampers 5, and among the relative acceleration applied to the payload 2, the variable damping damper 5 gently expands and contracts, thereby increasing the high frequency. Is transmitted, and the damping force obtained by multiplying the relative velocity obtained by integrating the acceleration component by the active damping ratio is obtained. Since the total of the two damping forces acts on the platform 4, the platform 4 is accelerated according to the mass including the payload 2. The acceleration / speed of the payload 2 that controls the skyhook damper system is not relative to the base 3 but absolute, so it cannot be controlled by passive components, and active control must be added. Can be realized for the first time. Specifically, the response frequency of the variable damping damper 5 is changed by changing the damping rate using the absolute acceleration / velocity obtained by the acceleration sensor.
[0025]
4 to 7 show graphs of acceleration generated in the payload 2 with respect to the vibration frequency applied to the rocket 1. FIG. 4 is based only on the passive vibration isolator. As shown in the figure, the payload 2 slightly accelerates with respect to the low frequency vibration of the rocket 1 of 2 Hz or less, and hardly accelerates with respect to the high frequency vibration of 7 Hz or more. However, since the resonance occurs in the vicinity of 5 Hz, extremely large acceleration occurs.
[0026]
FIG. 5 shows a passive vibration isolator in which the variable damping damper 5 is replaced with a fixed damping damper 5 in the vibration isolator of FIG. Although resonance in the vicinity of 5 Hz is suppressed, the high frequency cutoff characteristic is not good.
[0027]
FIG. 6 is based on the vibration isolator of the embodiment of FIG. The resonance in the vicinity of 5 Hz is eliminated, and the high frequency cutoff characteristic is excellent.
[0028]
FIG. 7 is based on the vibration isolator of the embodiment of FIG. Similar to FIG. 6, there is no resonance in the vicinity of 5 Hz, and the high-frequency cutoff characteristic is superior to that of FIG.
[0029]
Comparing the anti-vibration device of FIG. 1 with the anti-vibration device of FIG. 2, the anti-vibration device of FIG. 1 is excellent in performance and simple in configuration. The vibration isolator of FIG. 2 does not require power for moving the actuator, and can be configured to be lightweight.
[0030]
【The invention's effect】
The present invention exhibits the following excellent effects.
[0031]
(1) The resonance can be suppressed and the high frequency vibration can be suppressed, and the vibration isolation performance is improved.
[0032]
(2) Since the resonance in the horizontal direction can be suppressed, the clearance loss can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a vibration isolator showing an embodiment of the present invention. (A) is a side view, (b) is a top view excluding the platform.
FIG. 2 is a configuration diagram of a vibration isolator showing another embodiment of the present invention. (A) is a side view, (b) is a top view excluding the platform.
FIG. 3 is a control block diagram of the vibration isolator of FIG. 2;
FIG. 4 is a characteristic diagram showing a vibration transmission characteristic in a horizontal direction.
FIG. 5 is a characteristic diagram showing a vibration transmission characteristic in a horizontal direction.
FIG. 6 is a characteristic diagram showing a vibration transmission characteristic in a horizontal direction.
FIG. 7 is a characteristic diagram showing a vibration transmission characteristic in a horizontal direction.
[Explanation of symbols]
1 Launch Vehicle 2 Payload 5 Support Member

Claims (3)

A payload is mounted on the tip of the launch rocket via a plurality of extendable support members, a sensor for detecting the displacement amount of the payload is provided, and each of the above-described payloads is reduced so that the vibration of the payload is reduced based on the displacement amount. Provide a control circuit to control the expansion and contraction characteristics of the support member ,
The support members are arranged to extend and contract in the direction along the propulsion shaft at least three locations around the propulsion shaft, and are arranged to extend and contract in the direction toward the propulsion shaft at least two locations around the propulsion shaft, respectively. A payload anti-vibration device characterized by Said support member is constituted by an actuator which expands and contracts by the power, the payload of the vibration isolator according to claim 1, characterized in that so as to control the expansion and contraction motion of the actuator by the control circuit. The support member is composed of a variable damping damper that exhibits resistance to expansion and contraction, and the damping of the resistance is controllable, and the payload is tilted around the tip of the launch rocket at a predetermined tilt angle with respect to the propulsion shaft. a plurality of elastic supporting members for elastically supporting provided, the payload of the vibration isolator according to claim 1, characterized in that so as to control the damping characteristics of the variable damping damper by the control circuit.

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