JPH026298A - Positioning device for structures - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A9 Object of the Invention (1) Industrial Application Field The present invention relates to a device for positioning a structure using an actuator operated by an ultrasonic motor.
In particular, the present invention relates to a structure positioning device suitable for use in high vacuum space, where it is difficult to lubricate sliding parts.

(2) Conventional technology When constructing structures such as antennas on artificial satellites and space shuttles in outer space, it becomes necessary to control the position and attitude of these structures. In such cases, one end of a tension member such as a wire fixed to the structure is pulled by an actuator, and the tension of the tension member is adjusted to control the position and posture of the structure.

(3) Problems to be solved by the invention However, in the high vacuum of outer space, lubricating oil evaporates, so if a normal electric motor or hydropneumatic motor is used as an actuator, the sliding surface will run out of oil. There was a risk that this would occur and the function would stop. If the above-mentioned trouble occurs in outer space, it is extremely difficult to repair it, resulting in a waste of expensive materials and endangering precious human lives.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a structure positioning device using a non-lubricated actuator that can operate even in outer space where lubrication is difficult.

B1 Structure of the Invention (1) Semi-immersion to Solve the Problems In order to achieve the above problems, the structure positioning device of the present invention includes a large number of piezoelectric elements attached to the inner peripheral surface of a cylindrical elastic body. an ultrasonic motor that generates a traveling wave in the elastic body by applying a predetermined voltage to the piezoelectric element; and a tension member that is driven by abutting an intermediate portion of the ultrasonic motor on the elastic body of the ultrasonic motor. The present invention is characterized in that the structure is provided with an actuator constituted by the structure, and both ends of a tension member of the actuator are connected to a predetermined location of the structure to apply displacement to the structure.

(2) Function According to the present invention having the above-described configuration, when a large number of piezoelectric elements attached to the inner peripheral surface of the cylindrical elastic body of the ultrasonic motor expand and contract due to the application of voltage, the piezoelectric elements As the strain propagates, a traveling wave is formed on the surface of the elastic body. Then, the tension member whose intermediate portion is in contact with the elastic body is driven in one direction by the traveling wave, and a predetermined displacement for positioning is applied to the structure to which the tension end of the tension member is connected. arise.

(3) Examples Hereinafter, the present invention will be described in detail based on the drawings.

1 to 6 show an embodiment in which the positioning device for space structures according to the present invention is applied to a parabolic antenna, and FIG. 1 is a side view showing the parabolic antenna in an expanded state; Figure 2 is a plan view of the same, Figure 3 is a side view showing the parabolic antenna in a folded state, Figure 4 is a partially enlarged view of Figure 1, Figure 5 is a plan view of the actuator, and Figure 6 is the same. FIG.

As shown in Figures 1 to 4, this parabolic antenna P
is equipped with eight wooden aggregates 3 rotatably supported by a pivot 2 on the outer periphery of an upper ring 1a of a cylindrical main body 1 at equal intervals, and between the aggregates 3 there is a flexible , and a reflective film 4 made of a material that reflects radio waves is attached. The aggregates 3 are urged by a spring (not shown) attached to the pivot shaft 2 in a parallel closing direction as shown in FIG. folded into. When the aggregate 3 expands radially as shown in FIGS. 1 and 2, the reflective film 4 expands into a bowl shape to form a reflective surface of the antenna. Additionally, there are four wooden supports 5 erected on the top of the main body 1.
A reflective panel 6 that reflects radio waves is provided at the tip.

One end of a stainless steel band plate 8 as a tension member is fixed to the supporting part 3a provided at the tip of each aggregate 3, and the other end is fixed to the supporting part 3a provided at the tip of each aggregate 3. There is. The middle part of this strip plate 8 is wound around an actuator A attached to the outer periphery of the lower ring 1b of the main body 1, and by driving this actuator A and sending the strip plate 8 in the longitudinal direction, the parabolic antenna P Opening/closing and deciding the place are performed.

Next, the structure of the actuator will be explained based on FIGS. 5 and 6.

2n piezoelectric elements 10 are attached at equal intervals to the inner peripheral surface of a thin cylindrical elastic body 9 made of brass, and the piezoelectric elements 10 expand and contract by applying a voltage, and the expansion and contraction The direction of the voltage is reversed depending on the polarity of the voltage.

The piezoelectric elements 10 attached to the elastic body 9 are arranged so that the direction of expansion and contraction is alternately reversed, and each of the n piezoelectric elements located across the diameter has a separate one whose phase is shifted by 90 degrees. AC power supply 11a.

11b is connected. Therefore, the AC power supply 11a
, llb, each piezoelectric element 10 to which a voltage is applied expands and contracts in different phases, and a traveling wave is formed on the surface of the elastic body 9 to which this expansion and contraction propagates. In this way,
The above-mentioned elastic body 9, piezoelectric element 0, and AC type alla,
11b constitutes an ultrasonic motor 12 for driving the actuator A.

An intermediate portion of the aforementioned stainless steel band plate 8 is wound around the outer surface of the elastic body 9 of the ultrasonic motor 12, and this band plate 8 is driven in the longitudinal direction by the traveling wave.

The driving direction can be arbitrarily selected by reversing the phases of the AC power supplies 11a and 11b.

The openings at both ends of the elastic body 9 are closed by diaphragms 13 made of helium copper, and the arc generated in the piezoelectric element 10 is confined in the space formed by the elastic body 9 and the diaphragm 13. At this time, if the space is filled with an inert gas, safety can be further improved. A support member 14 made of lightweight material such as FRP or aluminum is fixed to the outside of this diaphragm, and a bolt 15 implanted in this support member 14 is screwed into the lower ring 1b of the main body 1 with a nut 16. The actuator A is attached by attaching the actuator A.

Next, the operation of one embodiment of the space structure positioning device according to the present invention having the above-described configuration will be described.

As shown by the chain line in FIG. 4, when the actuator A is driven from the folded state of the aggregate 3, the traveling wave formed on the outer surface of the elastic body 9 of the ultrasonic motor 12 causes the strip plate 8 to move in the direction of the arrow χ. (See Figure 4). Then, the aggregate 3 connected to one end of the strip plate 8 rotates to the position shown by the solid line, and the parabolic antenna P expands into a bowl shape. At this time, the other end of the strip 8 is automatically wound up during beam-shifting. Conversely, when the strip plate 8 is sent in the direction of the arrow Y by the actuator A, the other end of the strip plate 8 is unwound from the reel, and the aggregate 3 is moved along the chain line by the elastic force of the spring (not shown) attached to the pivot shaft 2. folded into position.

When the parabolic antenna P is in the expanded state, its reflective film 4 needs to be positioned symmetrically with the transmitter 6 as the center. For this purpose, the eight actuators A are each driven separately, and by finely adjusting the position of each aggregate 3, precise positioning of the reflection IIIJ, 4 is achieved.

Although the embodiments of the structure positioning device according to the present invention have been described in detail above, the present invention is not limited to the above embodiments, and without departing from the scope of the present invention described in the claims. Various minor design changes are possible.

For example, instead of using a strip as the tension member 8, a wire may be used, and the material thereof may be a polymeric material other than stainless steel. Instead of wrapping the tension member 8 around the elastic body 9, it is also possible to wrap it around the elastic body 9 one or more times.

Further, the method of applying voltage to the piezoelectric element 10 of the ultrasonic motor 12 is not limited to the method described in the above embodiment, but it is also possible to generate a traveling wave by applying voltages with slightly different phases to adjacent piezoelectric elements. be.

C3 Effects of the Invention According to the structure positioning device of the present invention described above, an ultrasonic motor is used as the actuator, and the tension member is driven by a traveling wave formed on the outer surface of the cylindrical elastic body. , there are no sliding parts between parts that require lubricant. Therefore, even in high-vacuum space, where it is difficult to lubricate sliding parts, the actuator can operate reliably and perform its functions reliably.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an expanded state of a parabolic antenna to which a positioning device for structures according to an embodiment of the present invention is applied, Fig. 2 is a plan view of the same, and Fig. 3 is a state of the parabolic antenna folded. 4 is a partially enlarged view of FIG. 1, FIG. 5 is a plan view of the actuator, and FIG. 6 is a side view of the actuator. 8... Band plate (tension member), 9... Elastic body, 10...
・Piezoelectric element, 12... Ultrasonic motor, 13... Diaphragm, A... Actuator, P... Parabolic antenna (accessory)

Claims (1)

[Claims] An ultrasonic motor that includes a large number of piezoelectric elements attached to the inner peripheral surface of a cylindrical elastic body, and generates traveling waves in the elastic body by applying a predetermined voltage to the piezoelectric elements. and a tension member that is driven by contacting the elastic body of the ultrasonic motor with its intermediate portion, and by connecting both ends of the tension member of this actuator to a predetermined location of the structure. A positioning device for a structure, characterized in that it applies displacement to the structure.