Antenna orienting device

Abstract

To provide an antenna orienting device which enables fine control in an orientation direction as represented by a case of antenna orientation in a moon landing machine and also enables reduction of the weight.SOLUTION: An antenna orienting device includes a physical pendulum mechanism U. An antenna part 1 is fixedly provided at the physical pendulum mechanism U to enable orientation control of the antenna part 1 to be performed according to a balanced attitude of the physical pendulum mechanism U.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to an antenna directing device. [Background technology]

[0002] Regarding existing technologies for pointing control of antennas used in space, for example, two-axis gimbals are used for pointing control of multi-frequency antennas for both transmission and reception in earth observation satellites such as ADEOS, ADEOS-2, and ALOS. For example, Non-Patent Document 1 is a technical document focusing on ALOS-2, which has an antenna diameter of 1.3 mφ, which is used in ADEOS to ALOS, but has been miniaturized to 70 cmφ and has reduced the automatic acquisition and tracking function. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Yamato, M; Tokunaga, H; Nakagawa, J. Mechanism for the Data Relay Satellite Communication System Antenna for the Advanced Land Observing Satellite-2 (ALOS-2). Mitsubishi Electric Technical Review, 2015, 89.3: 170-173. Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional antenna pointing control for satellites (technology that controls the physical orientation of the antenna itself as an object, rather than the directivity of the antenna) was unable to meet the technical requirements for antenna pointing control of the Earth-facing antenna for transmitting and receiving on a lunar lander (lunar station).

[0005] That is, in the case of the antenna of the lunar lander, (requirement 1) it is required to be lightweight in terms of transportation costs, and (requirement 2) it is necessary to minutely change and maintain the pointing direction because the pointing angle change required for the lunar station is gradual.

[0006] However, the two-axis gimbal used in satellite antenna pointing control has a wide pointing range of a hemispherical surface, so it is inappropriate for the fine control of the pointing direction in (Requirement 2). Moreover, a rear compartment equipped with an RF front end is required as equipment, and furthermore, a balance weight etc. is necessary, so the tendency of weight increase cannot be avoided, and it was also insufficient for achieving weight reduction in (Requirement 1).

[0007] Here, the lunar exploration activities as the background for using the earth-facing antenna at the lunar base will be briefly explained.

[0008] Figure 1 is a diagram schematically showing an example of the system configuration of lunar exploration activities. The initial base of lunar exploration activities is within the Antarctic crater where permafrost forms (water resources are expected). Since the earth cannot be seen from spacecraft (including landing vehicles, unmanned and manned rovers, and extravehicular astronauts) in this area, a plan to relay through a lunar orbiting satellite is being promoted. Also, a lunar orbiting satellite is used for communication with rovers outside the base. When communicating directly from the lunar orbiting satellite to the earth, a plurality of antennas with different pointing directions are required in the directions of lunar surface users (landing vehicles, unmanned and manned rovers, etc.) and the earth direction. In particular, the earth-facing antenna needs to cover the entire globe, and there are difficulties in satellite mountability. Therefore, it is effective to provide a lunar base in the direction of lunar surface users, collect data from each spacecraft, and transmit it to the earth collectively. Also, by providing a base station at the edge of the Antarctic crater, miniaturization of user terminals can be achieved.

[0009] Figure 2 is a diagram schematically showing the positional relationship between the moon and the earth, which is the background for the need for fine control of the pointing direction in (Requirement 2) above. From the following characteristics, the earth-pointing antenna angle range of the lunar base is approximately ±8° at most, and the antenna driving angular velocity is a slow change of 10-4 ° / second or less, and fine control corresponding to this change is required. ● The orbital inclination angle of the moon: 5.1°, the equatorial inclination angle: 1.5°, and the deviation from the earth direction is ±7° or less with a 27-day cycle. (EL direction ±5.1° and AZ direction: ±1.5° on the lunar surface) ● The distance between the moon and the Earth is as far as 380,000 km, and the entire Earth is included within about ±1° from the lunar surface (the visible time of the moon is 10 to 14 hours). The maximum value of the pointing range of the lunar station is 6.1° in the EL direction and ±2.5° in the AZ direction, which is the above added value.

[0010] In view of the problems of the prior art as described above, an object of the present invention is to provide an antenna pointing device suitable for use in an Earth-facing antenna or the like when a lunar lander is used as a lunar station, which enables fine control of the pointing direction and can achieve weight reduction.

Means for Solving the Problems

[0011] In order to achieve the above object, the present invention is an antenna pointing device including a physical oscillator mechanism, wherein an antenna unit is fixedly provided in the physical oscillator mechanism, and the pointing control of the antenna unit is realized according to the balance posture of the physical oscillator mechanism.

Effects of the Invention

[0012] According to the present invention, since a simple mechanism of a physical oscillator mechanism is directly used for antenna pointing, it is possible to realize fine control of the pointing direction and weight reduction due to a simple structure.

Brief Description of the Drawings

[0013]

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Modes for Carrying Out the Invention

[0014] FIG. 3 is a structural diagram of the lunar station device 10 according to an embodiment, and is a diagram shown as a schematic perspective view. For the lunar station device 10 in the state CA on the upper stage side, the state CB on the lower stage side represents the lunar station device 10 in a state where some parts are removed from the state CA. The lunar station device 10 is configured with a rectangular parallelepiped housing as its overall appearance, and includes an upper surface portion 1, four side surface housing portions 2, a central support column portion 3, a bottom surface portion 4, and four leg portions 5. The state CB on the lower stage side represents a state where the upper surface portion 1 is removed from the lunar station device 10 in the state CA. As will be described later, the upper surface portion 1 is fixed to the side surface housing portion 2, and in order to remove the upper surface portion 1 as in the state CA, it is actually necessary to disassemble the lunar station device 10. That is, the upper surface portion 1 is not configured to be detachable from the lunar station device 10 as a normal operation of the lunar station device 10. The state CA of the lunar station device 10 is shown as a state where the upper surface portion 1 is removed intentionally to explain the structure, shape, etc. of the portions that are hidden and not visible by the upper surface portion 1.

[0015] Note that the lunar station device 10 according to the present embodiment is an antenna pointing device 10, and as one of its suitable applications, it can perform antenna pointing control in a lunar station and is not limited to use in a lunar station. In this specification, as an example of the description of the antenna pointing device 10, the lunar station device 10, which is the suitable application, will be described. Also, each figure including FIG. 3 referred to in the following description is merely a schematic structural diagram (excluding FIG. 5 of the flowchart) for explaining that antenna pointing control can be realized by using the housing structure in the antenna pointing device 10 according to the embodiment of the present invention. It is obvious to those skilled in the art that the actual scale, the size relationship of each part, etc. are not limited to those shown, and various changes etc. are possible without departing from the spirit of the embodiment of the present invention. Also, from the viewpoint of clarifying and simplifying the description, the case where the shape has symmetry and each part is configured with the same shape will be described, but similarly, it is obvious to those skilled in the art that various changes etc. are possible without departing from the spirit of the embodiment of the present invention. For example, a structure with some breakdown of symmetry may be acceptable.

[0016] On the upper surface portion 1 of a plate shape (a rectangular parallelepiped shape with a short height direction with respect to the rectangular sizes of the upper and lower surfaces), there are provided an antenna portion AT, a fixing portion 11 for fixing the antenna portion AT to the flat portion of the upper surface portion 1, and a rotating portion 12 constituted by a hinge mechanism (hinge) or the like for rotating the antenna portion AT to a raised state when the fixing by the fixing portion 11 is released. The rotating portion 12 is driven by a driving mechanism such as a motor (not shown), so that when the fixing by the fixing portion 11 is released, the antenna portion AT can be rotated and raised. By providing a primary radiator (including a power feeding portion for receiving in the 7 GHz band, transmitting in the 8.4 GHz band, receiving in the 23 GHz band, transmitting in the 27 GHz band, etc., not shown) in the vicinity of the fixing portion 11, the antenna portion AT can be made to function as a reflector.

[0017] The antenna portion AT is configured to be substantially circular in a top view, the fixing portion 11 is provided on the left end side of the circular outer periphery, and the rotating portion 12 is formed on the opposite right end side, so that the fixing by the fixing portion 11 and the raising of the antenna portion AT by the rotating portion 12 when the fixing is released are made possible. The rotating portion 12 includes an elastic body such as a spring, is biased during fixation, and when the fixation is released, the bias is released, so that the antenna portion AT can be brought into a raised state by its elastic force. The fixing by the fixing portion 11 can be released by being burned through by a release mechanism such as a heater (not shown). (Since there is no oxygen for combustion on the lunar surface, "burning through" includes fusing by heating, and the same shall apply hereinafter.) As the antenna pattern of the antenna portion AT, for example, a parabolic antenna or a Cassegrain antenna having a rotating parabolic pattern may be used. Since the direction of the Earth is near the lunar horizon, it is preferable to use an offset type. As the role of transmission and reception, it is for receiving in the 7 GHz band, transmitting in the 8.4 GHz band, receiving in the 23 GHz band, and transmitting in the 27 GHz band, and the 23 GHz band may be provided with an automatic tracking mechanism for direction control.

[0018] As shown in the state CB, the four side housing parts 2 are configured to have the same shape as each other (including the case where they are the same shape in a mirror image relationship in the front-back direction and the left-right direction), and are formed from a rectangular parallelepiped shape by cutting out a rectangular parallelepiped shape obtained by dividing the rectangular parallelepiped-shaped central support part 3 located at the center of these four into four equal parts. That is, it has the shape of a "concave hexagonal column" as a columnar body with concave hexagonal upper and lower surfaces. As described above, the scale and the like are not limited to those shown in the drawings, and the central support part 3 may be smaller and thinner than that shown in the state CB in FIG. 3 and the like, and may be located on the central side, and the four side housing parts 2 may occupy more space on the central side.

[0019] FIG. 4 is a structural diagram of the lunar station device 10 in the state CC in which the four side housing parts 2 are further removed from the state CB in FIG. 3. As shown therein, the central support part 3 is configured in a rectangular parallelepiped shape and is fixed at its center in a top view with respect to the bottom part 4. On the upper surface of the central support part 3, as will be described in detail later, for configuring the four side housing parts 2 as physical oscillators (so-called yajirobe mechanisms), the fulcrum parts 31 of the physical oscillators are formed in a convex shape.

[0020] On the bottom surface side of the plate-shaped (rectangular parallelepiped shape with a short height direction with respect to the rectangular sizes of the upper and lower surfaces) bottom part 4, four leg parts 5 are formed. By the leg parts 5 contacting the lunar surface, it becomes possible to install the lunar station device 10 on the lunar surface. Among the four leg parts 5 of the front left, front right, rear left, and rear right, the rear left leg part 5 is in a state of being hidden behind the bottom part 4 in the drawing and is not visible. The leg part 5 is provided with a length adjustment mechanism 51. The length adjustment mechanism 51 can be configured as, for example, a mechanism that expands and contracts a ball screw mechanism (not shown) and the like by a drive mechanism such as a motor (not shown). By adjusting the lengths of the four leg parts 5 respectively by the four length adjustment mechanisms 51, it is possible to install the lunar station device 10 in a horizontal state with respect to the lunar surface (a state where the lunar station device 10 stands vertically on the lunar surface).

[0021] FIG. 5 is a flowchart of antenna direction control in the lunar base device 10 according to an embodiment. Hereinafter, while explaining each step of FIG. 5, the details of the configuration of the lunar base device 10 will be further described with reference to separate drawings (FIGS. 6 and later).

[0022] In step S1, after transporting the lunar base device 10 from the Earth to the lunar surface by a transportation means such as a rocket, the lunar base device 10 is landed on the lunar surface and horizontally installed on the lunar surface. The horizontal installation is possible by adjusting the lengths of the four legs 5 by the four length adjustment mechanisms 51 described above.

[0023] In step S2, after expanding the lunar base device 10, the antenna unit AT is raised. FIG. 6, which is a perspective view, is one of the figures for explaining the expansion and contraction mechanism 6 in the lunar base device 10. This FIG. 6 shows only the upper surface portion 1 and the upper surface portions 2U of the four side housing portions 2 as a perspective view of the lunar base device 10 in state CA. On each of the upper surface portions 2U of the four side housing portions 2, there is also a portion below the upper surface portion 2U, so that the side housing portion 2 having a concave hexagonal column shape is configured. In FIG. 6, which is a perspective view, only the left front side housing portion 2 out of the four is shown with the lower portion indicated by a broken line.

[0024] Note that in FIG. 6, the configuration related to the antenna unit AT in the upper surface portion 1 is not shown, and the same is omitted in FIGS. 7, 8, 9, 13, and 14 described later.

[0025] As schematically shown by the symbol arrows in FIG. 6, the expansion and contraction mechanism 6 is configured as four expansion and contraction mechanisms 6, each existing for each of the four side housing portions 2. The expansion and contraction mechanism 6 is fixed to the bottom surface side of the upper surface portion 1, and the expansion and contraction mechanism 6 is fixed to the upper surface portion 2U of the side housing portion 2. Thus, the upper surface portion 1 and the side housing portion 2 are connected via the expansion and contraction mechanism 6, and when the expansion and contraction mechanism 6 expands and contracts, the side housing portion 2 is configured to be movable by radially expanding or contracting from the center of the lunar base device 10.

[0026] In FIG. 6, both the a-a line and the b-b line are the common diagonals of the outer peripheral rectangle of the upper surface portion 1 and the outer peripheral rectangles of the four side housing portions 2 in the top view. FIG. 7 shows a vertical cross-sectional view of the lunar station device 10 along the a-a line or the b-b line, only in the vicinity of the upper part of the lunar station device 10. Due to the symmetry of the shape, the cross-sectional view along the a-a line and the cross-sectional view along the b-b line are the same, and both are as shown in FIG. 7.

[0027] In FIG. 7, the contracted state of the lunar station device 10 is shown as state Ca, and the extended state of the lunar station device 10 is shown as state Cb. (Note that FIGS. 3 and 6 described above show the configuration of the lunar station device 10 in the contracted state Ca.) As shown in FIG. 7, the expansion and contraction mechanism 6 includes a central side bearing portion 61, a rotating shaft portion 62 configured as a rotating shaft composed of a long bolt (male thread), and an outer peripheral side bearing portion 63. At the center of the bottom surface side of the upper surface portion 1, a concave receiving portion 13 for receiving the convex fulcrum portion 31 of the central support portion 3 is formed, and the central side bearing portion 61 is fixedly installed on the side surface of this receiving portion 13.

[0028] The central side bearing portion 61 is configured using a ball bearing mechanism or the like, so as to rotatably hold the rotating shaft portion 62, receive the rotational force from a drive mechanism (not shown), and rotate the held rotating shaft portion 62.

[0029] The outer peripheral side bearing portion 63 and the rotating shaft portion 62 as a bolt shaft constitute a known ball screw mechanism. That is, the outer peripheral side bearing portion 63 includes a nut, a plurality of steel balls, and a circulation mechanism for circulating the steel balls, and rotatably holds the rotating shaft portion 62, and is configured to be movable in the axial direction of the rotating shaft portion 62 in conjunction with the rotation of the rotating shaft portion 62.

[0030] For example, when the rotating shaft portion 62 rotates forward in a predetermined direction, the outer peripheral side bearing portion 63 moves in a direction away from the central side bearing portion 61, and when the rotating shaft portion 62 rotates reversely in a direction opposite to the predetermined direction, the outer peripheral side bearing portion 63 can be configured to move in a direction approaching the central side bearing portion 61.

[0031] In this way, as the rotating shaft portion 62 rotates, the outer peripheral side bearing portion 63 that constitutes the ball screw mechanism moves, and the side housing portion 2 to which the outer peripheral side bearing portion 63 is fixed at the upper surface portion 2U moves integrally with the outer peripheral side bearing portion 63. As a result, the lunar station device 10 can continuously switch between the contracted state Ca and the extended state Cb as shown in FIG. 7.

[0032] FIG. 8 is a view showing the contracted state Ca of FIG. 7 as a cross-sectional view extending over the entire lunar station device 10, and FIG. 9 is a view showing the extended state Cb of FIG. 7 as a cross-sectional view extending over the entire lunar station device 10. The outer peripheral side bearing portion 63 has the side housing portion 2 having a load fixed thereto via the upper surface portion 2U, and by adopting a configuration in which the side housing portion 2 hangs with respect to the rotating shaft portion 62, the side housing portion 2 can move in the axial direction of the rotating shaft portion 62 integrally with the outer peripheral side bearing portion 63 that constitutes the ball screw mechanism.

[0033] Wheels 2W that can also serve as a holding release mechanism may be provided on the bottom surface of the side housing portion 2. In the contracted state Ca, the side housing portion 2 is mounted on the bottom surface portion 4 via the wheels 2W, and by adopting a configuration in which it is fixed to eliminate the adverse effects of vibrations during transportation, even when the side housing portion 2 has a certain amount of load, after transportation, the fixation is released and the lunar station device 10 can be smoothly extended from the contracted state Ca to the extended state Cb with a small rotational force without requiring an excessive rotational force. The wheels 2W have a function of locking rotation in the contracted state Ca and fixing the side housing portion 2 to the bottom surface portion 4 by being adhered to the bottom surface portion 4 or the like. When extending to the extended state Cb, the rotation lock of the wheels 2W can be released, and the adhesion and fixation state to the bottom surface portion 4 can be released by burning it off with a heater or the like (not shown).

[0034] As a modification to the configuration of FIGS. 8 and 9, the wheel 2W may be omitted, and the side housing portion 2 may be arranged in a floating state with a predetermined interval provided on the bottom portion 4, or the side housing portion 2 may be in a state of contacting (mounted) on the bottom portion 4. Instead of or in addition to fixing / releasing the side housing portion 2 to / from the bottom portion 4 by the wheel 2W as the holding release mechanism, similarly, a holding release mechanism (not shown) for fixing / releasing the side housing portion 2 to / from the central support portion 3 (fixed by burning with a heater or the like when releasing the fixation) may be provided. That is, since the contracted state Ca is also the state when transporting the lunar base device 10 by a rocket or the like, in order to suppress the adverse effects caused by the vibration during transportation of the extendable side housing portion 2 in the lunar base device 10, the side housing portion 2 may be fixed in various manners as described above.

[0035] FIG. 10 is a horizontal sectional view taken along the c-c line of the lunar base device 10 in the contracted state Ca of FIG. 8, and FIG. 11 is a horizontal sectional view taken along the c-c line of the lunar base device 10 in the extended state Cb of FIG. 9. As shown in FIGS. 9 and 11, in the extended state Cb, the side housing portion 2 can be extended to a position completely separated from the range of the horizontal plane formed by the bottom portion 4 to the outer peripheral side, and then float from the plane formed by the bottom portion 4. By being in the floating state, the lunar base device 10 is configured as a physical pendulum described later, and the physical pendulum mechanism can swing with respect to the fulcrum, and it is possible to balance in various postures.

[0036] In step S2, as described above, by applying a rotational driving force in the extending direction to the expansion and contraction mechanism 6, the lunar base device 10 can be extended from the contracted state Ca to the extended state Cb. In step S2, further in the extended state Cb, as shown in FIG. 12, by raising the antenna portion AT in the rotational direction AR on the upper surface portion 1, antenna installation can be realized in the lunar base device 10. (The raising mechanism has been described as shown in FIG. 3.)

[0037] Here, the antenna directivity control process of the antenna unit AT in the lunar base unit 10 as the antenna directivity device 10 can be realized because the lunar base unit 10 in the extended state Cb constitutes a physical oscillator (yajirobe).

[0038] That is, as shown in FIG. 9, the lunar base unit 10 in the extended state Cb is in a state composed of an upper-side directivity control unit U and a lower-side lunar surface fixing unit D, which are divided by a fulcrum formed by the receiving unit 13 and the fulcrum part 31.

[0039] The directivity control unit U is composed of an upper surface part 1 (including components related to the antenna unit AT), a telescopic mechanism 6, and four side housing parts 2 extended by the telescopic mechanism 6. The entire directivity control unit U is integrated to form a physical oscillator that can swing with respect to the lunar surface fixing unit D about the fulcrum. The lunar surface fixing unit D is composed of a central support column part 3, a bottom surface part 4, and four leg parts 5, which provide a fulcrum for the physical oscillator and maintain a fixed state on the lunar surface.

[0040] Here, although not shown as an internal cavity in FIG. 9 and the like, in the lunar base unit 10, the four side housing parts 2 are used as housings to fix and store equipment (devices) such as electronic devices that undertake various processes (various processes required in lunar surface activities such as measurement, control, observation, and communication) inside. Therefore, in this embodiment, by utilizing the mass of the equipment as the weight of the physical oscillator, there is an effect that it is not necessary to provide a dedicated weight separately from the equipment.

[0041] As is known as the mechanism of the physical oscillator, the physical oscillator has a balanced state without falling with respect to the fulcrum and can swing stably with respect to the balanced state. In this embodiment, the directivity control unit U is configured such that its center of gravity is located below the fulcrum, and the mass distribution including the internal storage equipment of the four side housing parts 2, the mass distribution of the telescopic mechanism 6, and the mass distribution of the upper surface part 1 in the state where the antenna unit AT is raised may be set.

[0042] Also, in a state where the orientation control unit U of the physical pendulum is balanced and stationary, the orientation control of the antenna unit AT will be realized. In the present embodiment, since the length of extending the side housing portion 2 to the outer peripheral side can be adjusted for each of the four side housing portions 2 by the telescopic mechanism 6 provided in each of the four side housing portions 2, by adjusting the four extension lengths, the posture of the balanced state of the orientation control unit U can be changed, and the orientation control for realizing the antenna unit AT in a desired direction can be realized.

[0043] That is, since the balanced posture DR can be calculated from mechanical calculations as DR = DR(L1, L2, L3, L4) as a function of the extension lengths L1, L2, L3, L4 of each of the four side housing portions 2 (the mass distribution of the orientation control unit U determined according to these), the extension lengths L1, L2, L3, L4 for realizing the desired posture DR can be determined from the inverse function of the said function, and the antenna unit AR can be orientation-controlled in a desired direction using the said inverse function. Note that the posture DR can be determined with two degrees of freedom such as two angles.

[0044] Here, in one embodiment, the lunar base apparatus 10 may further include a stabilization mechanism to stabilize the stationary state of the orientation control unit U in the balanced posture DR (for example, when some mechanical disturbance is applied, the orientation control unit U will shift from the stationary state to the swinging state, so the stationary state is stabilized against such disturbances). According to the stabilization mechanism, in addition to stabilizing the stationary state in the balanced posture, it is also possible to stabilize it as a stationary state after changing the balanced posture.

[0045] FIG. 13 is a diagram showing a lunar station apparatus 10 configured by adding a stabilization mechanism 60 to the lunar station apparatus 10 in the extended state Cb of FIG. 9. The stabilization mechanism 60 can be provided for each of the four side housing portions 2 and the central support portion 3 as a mechanism that enables a change in the posture of the pointing control unit U by pulling the pointing control unit U from the lunar surface fixing portion D. The stabilization mechanism 60 includes a towing cable (pulling string) 65 and a spooling mechanism or the like, and a spooling portion 64 that can adjust the externally exposed length of the towing cable 65 (the length of the portion of the entire length of the towing cable 65 that is not wound and stored and functions as a pulling string by being released from the storage position and exposed to the outside).

[0046] As shown in FIG. 13, the spooling portion 64 can be fixedly installed, for example, on the side surface of the central support portion 3. One end of the towing cable 65 is fixed to the spooling portion 64, and the other end of the towing cable 65 that can be wound up / paid out by the reel mechanism constituted by the spooling portion 64 can be fixed to a predetermined position of the side housing portion 2. In the example of FIG. 13, the fixing position at the other end is set as the upper position up of the side housing portion 2, but it may be set at the middle position mp, or may be set at the lower position dp, or may be set at other positions including intermediate positions between these. The fixing position of the towing cable 65 may be determined in consideration of various matters. For example, if the lower position dp is the position where the posture change of the pointing control unit U can be performed most effectively, it may be fixed at the lower position dp, or if it is effective in preventing interference with other harnesses (not shown), etc., it may be fixed at the middle position mp. From the same viewpoint, although the spooling portion 64 is provided near the upper part of the central support portion 3 in FIG. 13, it may be provided near the middle part, near the lower part, or may be provided on the bottom surface portion 4.

[0047] In this way, by connecting the direction control unit U and the lunar surface fixing unit D that constitute the physical pendulum with the cable 65, and pulling the direction control unit U that can easily swing or rotate around the fulcrum due to the presence of external disturbances from the lunar surface fixing unit D, the balance posture of the direction control unit U can be stably maintained in a stationary state. One end of the cable 65 is fixed to the four side housing parts 2 that are located on the radially expanding outer periphery of the direction control unit U that constitutes the physical pendulum and occupy most of the mass of the physical pendulum, so that the stationary state can be effectively stabilized.

[0048] When the four spool parts 64 wind up / pay out the corresponding cables 65 respectively, the arrangement of the stabilization mechanism 60 may be configured as an arbitrary arrangement such that the other components of the lunar base device 10 do not interfere with the respective cables 65. In FIG. 13, the cable 65 is depicted in a deflected state, but when stabilizing the stationary state, at least one of the four cables 65 can be in a state of being stretched in a substantially straight line with tension.

[0049] In each of the balance postures DR(L1, L2, L3, L4) corresponding to the extended lengths L1, L2, L3, L4, the lengths N1, N2, N3, N4 in which the four cables 65 are exposed linearly with tension to maintain the balance posture DR(L1, L2, L3, L4) can be determined in advance by mechanical calculation. Therefore, by setting the reel rotation position of the spool part 64 by a rotation drive mechanism (not shown) so that the four cables 65 are exposed at the set lengths N1, N2, N3, N4, the direction control unit U can be stably stationary in the balance posture.

[0050] At this time, since the principle of a physical pendulum (a yokel) is used, by pre-configuring the pointing control unit U so that the center of gravity is located from the fulcrum, there is an advantage that the pointing direction can be made variable without falling by a small force. That is, regarding the drive mechanism such as a motor for pulling the tow rope 65 in the spool unit 64, the driving force may be small, and miniaturization and weight reduction of the equipment can be achieved. Furthermore, on the lunar surface, the gravity is 1 / 6 of that on the earth. For example, a 300 kg spacecraft is reduced to the equivalent of 50 kg. Accordingly, less force for pointing control is required.

[0051] Regarding the lengths N1, N2, N3, N4, the bent state (which corresponds to a state having no tension when the mass is approximated to zero) may be treated as an exception value or infinity for the length, or the mechanical calculation may be performed without approximating the mass of the tow rope 65 to zero and including the bent state, and the lengths N1, N2, N3, N4 for stably holding the equilibrium posture DR (L1, L2, L3, L4) may be calculated according to the equilibrium posture.

[0052] In step S2, as described above, after setting the extended lengths L1, L2, L3, L4 so that the antenna unit AT is pointed in a desired direction, by providing the four tow ropes 65 with the exposed lengths N1, N2, N3, N4 in the stabilization mechanism 60, the stationary state in the desired direction can be stabilized.

[0053] In step S3, at each subsequent time, control is performed to direct the antenna unit AT in the direction in which it should be directed at that time. This control may be performed by changing the exposed lengths N1, N2, N3, N4 of the four guy wires 65 while keeping the extended lengths L1, L2, L3, L4 set in step S2 as they are, applying an external force from at least one of the guy wires 65 to the balanced state of step S2, and changing from the balanced state of step S2. By setting the degree of change to a minute range, the direction control can be stably executed. Alternatively, in step S3 as well, similar to step S2, the extended lengths L1, L2, L3, L4 are set so that the direction in which the antenna unit AT should be directed at that time is in a balanced state, and the exposed lengths N1, N2, N3, N4 of the four guy wires 65 are set to stabilize the balanced state.

[0054] Alternatively, in step S3, the setting of the lengths of the extended lengths L1, L2, L3, L4 that determine the balanced posture is performed discretely at long intervals (for example, every hour), and the adjustment of the balanced posture at short intervals (for example, every minute) within the long interval is realized by changing the exposed lengths N1, N2, N3, N4 of the four guy wires 65 with respect to the extended lengths L1, L2, L3, L4 fixed in the long interval.

[0055] As described above, according to the embodiment of the present invention, (1) the lunar base device 10 (antenna direction device 10) as the structure of the lunar lander is radially extended from the center side to the outer peripheral side, and with a structure that maintains balance based on the principle of a weathervane (physical oscillator) and is difficult to roll over, antenna direction control can be realized by setting the balanced posture of the weathervane. Also, (2) by changing the center of gravity position by pulling in / releasing the extended structure (direction control unit U) and the central structure (lunar surface fixing unit D) with a spool (winding up / unwinding the guy wire 65 in the stabilization mechanism 60), the direction of pointing can also be finely changed.

[0056] The antenna direction device 10 of this embodiment is not limited to use in a lunar base, but when used in a lunar base, various effects as described below can be achieved.

[0057] ●In the 2030s to 2040s, lunar activities will become active, and the utilization of lunar stations can be expected as a base for developing communication infrastructure including the circumlunar region. ●By means of a lunar station, the communication capabilities of lunar spacecraft (including lunar landers, unmanned and manned rovers, and residential area communication devices as manned activity bases) and circumlunar spacecraft for observation, communication, and positioning are relaxed, and the resource burden of mass and power is reduced. ●The communication counterpart of a circumlunar satellite is limited to the lunar surface, and an Earth-facing antenna for the circumlunar satellite becomes unnecessary. ●The Earth station is only for the side facing the lunar station, and a large number of Earth stations for each user spacecraft (including lunar activity spacecraft) become unnecessary. ●By routing circumlunar data through a lunar station, frequency allocation between the Earth and spacecraft becomes easier. ●The lunar station is equipped with a balance detector and a function to correct the inclination of the landing point by a ball screw, and it is possible to keep the mass point of the lunar station horizontal on the lunar surface. (It can also cope with the unstable lunar surface.) ●The gravity on the lunar surface is 1 / 6 that of the Earth and is lightweight. If the center of gravity is lower than the fulcrum, the divided mass points can balance with the distance difference from the fulcrum. Furthermore, since the pointing range is as narrow as ±8° or less, pointing control can be achieved with a slight change in mass balance. ●For changes in mass balance, fine pointing direction control is possible with the length of the ball screw and a strong cable reel from the lunar landing section, and the increase in mass is also small.

[0058] Hereinafter, various supplementary examples, additional examples, alternative examples, etc. regarding embodiments of the present invention will be described.

[0059] (1) By contributing to lunar resource development and the like, the embodiments of the present invention can contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0060] (2) The force transmission mechanism for extending the lunar upper unit 10 can be designed in various ways. For example, as schematically shown in FIG. 14, the driving force for the four central side bearing parts 61 to rotate their respective rotating shaft parts 62 and the driving force for the four winding parts 64 to wind up / pay out their respective pulling cables 65 can each be realized by the driving force provided by a motor mechanism as a single driving mechanism, thereby reducing the weight of the equipment.

[0061] That is, as shown on the left side of FIG. 14, for example, the motor mechanism is arranged at the center position of the horizontal plane in the receiving part 13 of the upper surface part 1, and the motor mechanism itself is rotatable 360° on the horizontal plane, so that its output shaft can be selectively engaged with and rotationally driven by each of the ball screws #1 - #4 (the ball screw mechanisms of the four central side bearing parts 61). Similarly, for example, the motor mechanism is arranged at the center position of the horizontal plane in the central support part 3, and the motor mechanism itself is rotatable 360° on the horizontal plane, so that its output shaft can be selectively engaged with and rotationally driven by each of the winders #1 - #4 (the winding / paying out mechanisms of the four winding parts 64).

[0062] Also, as shown on the right side of FIG. 14, in a state where the output shaft of the motor mechanism has selected one of the driving targets, the driving target can be rotated forward or backward. That is, the output shaft M of the motor mechanism M is assumed to rotate in a predetermined direction. During forward rotation, it can be driven forward as "output shaft MA → power forward transmission mechanism A3 → power transmission mechanism A4 → driving target A5", and during reverse rotation, it can be driven in reverse as "output shaft MA → power reverse transmission mechanism A2 → power transmission mechanism A4 → driving target A5". It is also possible to provide only the forward driving mechanism and switch the forward / reverse rotation of the motor.

[0063] (3) In the embodiment shown in FIG. 7 and the like, a ball screw mechanism is adopted for the outer peripheral side bearing portion 63 of the telescopic mechanism 6. However, conversely, a ball screw mechanism may be adopted on the central side. FIG. 15 is a diagram for explaining such a reverse method as a modification of FIG. 7. The telescopic mechanism 6 includes a central side bearing portion 71, a rotary shaft portion 72 configured as a rotary shaft composed of a long bolt (male screw), and an outer peripheral side bearing portion 73 (each replacing the central side bearing portion 61, the rotary shaft portion 62, and the outer peripheral side bearing portion 63 in FIG. 7). Similarly in FIG. 15, a receiving portion 14 is formed on the upper surface portion 1 as a replacement for the receiving portion 13 in FIG. 7. That is, a concave receiving portion 14 for receiving the convex fulcrum portion 31 of the central support portion 3 is formed at the center on the bottom surface side of the upper surface portion 1, and the central side bearing portion 71 is fixedly installed on the side surface of this receiving portion 14.

[0064] A space is formed in the receiving portion 14 to accommodate the rotary shaft portion 72 that moves in the axial direction.

[0065] The outer peripheral side bearing portion 73 is configured using a ball bearing mechanism or the like to rotatably hold the rotary shaft portion 72.

[0066] The central side bearing portion 71 and the rotary shaft portion 72 as a bolt shaft constitute a known ball screw mechanism. That is, the central side bearing portion 71 includes a nut, a plurality of steel balls, and a circulation mechanism for circulating the steel balls, and rotatably holds the rotary shaft portion 72. In conjunction with the rotation of the rotary shaft portion 72, the rotary shaft portion 72 and the outer peripheral side bearing portion 73 are configured to be integrally movable in their axial directions. The central side bearing portion 71 also receives a rotational force from a drive mechanism (not shown) and rotates the held rotary shaft portion 72.

[0067] For example, when the rotary shaft portion 72 rotates forward in a predetermined direction, the outer peripheral side bearing portion 73 and the rotary shaft portion 72 move in a direction away from the central side bearing portion 71 integrally. When the rotary shaft portion 72 rotates reversely in a direction opposite to the predetermined direction, the outer peripheral side bearing portion 73 and the rotary shaft portion 72 can be configured to move in a direction approaching the central side bearing portion 71 integrally.

[0068] In this way, as the rotating shaft portion 72 rotates, it moves axially as a ball screw mechanism, and the side housing portion 2 where the outer peripheral side bearing portion 73 is fixed to the upper surface portion 2U moves integrally with the outer peripheral side bearing portion 73. Thus, the lunar base unit 10 can continuously switch between a contracted state Ca and an extended state Cb as shown in FIG. 15, similar to the case of the example in FIG. 7.

[0069] As shown in FIGS. 7, 8, etc., the side housing portion 2, the central support column portion 3, etc. can be formed as a housing, and various devices for various purposes can be fixed and stored inside. Wiring such as wires, harnesses, and cables may be provided between the devices in the side housing portion 2 and the devices in the central support column portion 3, or between the devices arranged in different side housing portions 2 so that electrical signals, electric power, etc. can be transmitted to each other. The wiring may be provided, for example, in a lightweight and bent state so as to minimize the influence on the balance posture of the direction control unit U as a physical oscillator.

[0070] (4) In FIGS. 9, 10, etc., an example is shown where there are four side housing portions 2 that radially extend in directions forming 90° angles with each other, but the number and angle may be changed to other values. For example, the direction control unit U's physical oscillator may be configured by having three side housing portions 2 that radially extend in directions forming 120° angles with each other. In this case, in the contracted state Ca, the three side housing portions 2 may have a cylindrical shape instead of a rectangular parallelepiped shape.

[0071] (5) Regarding the fulcrum between the direction control unit U and the lunar surface fixing portion D, in the above description, it is assumed that they are not fixed to each other with concave and convex shapes so that the direction control unit U can swing freely. However, in the non-fixed state, there is a risk of adverse effects due to vibrations during transportation. To prevent this, a mechanism as shown in FIG. 16 may be used to form the fulcrum so that it is fixed during transportation and a freely swingable fulcrum is formed by releasing the fixation and extending it.

[0072] That is, FIG. 16 is a diagram schematically showing a fulcrum structure according to a modification example, which is formed by a receiving portion 15 according to a modification example of the receiving portions 13 and 14 and a fulcrum structure 32 according to a modification example of the fulcrum portion 31. The fulcrum structure 32 includes a fulcrum portion 321, an elastic extension structure 322 composed of an elastic body such as a spring and an axis (not shown) passing through its center, and a cylindrical portion 323 for storing the elastic extension structure 323. One end of the rod-shaped elastic extension structure 323 is fixed to the fulcrum portion 321, and the other end is fixed to the cylindrical portion 323.

[0073] In FIG. 16, state C1 is the fixed state of the fulcrum structure 32, and state C2 shows the extended structure of the fulcrum structure 32 after releasing the fixed state. In the fixed state C1, the bottom surface of the receiving portion 15 is fixed to the upper surface of the cylindrical portion 323 by adhesion or the like, and the convex portion of the fulcrum portion 321 is pressed against the concave portion of the receiving portion 15 by the elastic extension structure 323 that is elastically expanded and contracted inside. Therefore, it is possible to prevent the adverse effects of vibration during transportation. Although not shown in FIG. 16, a space for the center rod to fit in the fixed state C1 for ensuring the rigidity of the elastic extension structure 323 during extension may be provided as a hole in the inner bottom surface of the cylindrical portion 323. Alternatively, an extension structure using a screw mechanism may be used instead of the elastic extension structure 323.

[0074] In order to shift from the fixed state C1 to the extended state C2, it is only necessary to release the fixation by adhesion or the like between the bottom surface of the receiving portion 15 and the upper surface of the cylindrical portion 323 by operating a heater or the like (not shown). By releasing the fixation, the elastic force that has been expanding and contracting the elastic extension structure 323 is released, and the fulcrum portion 321 is pushed upward and extended to shift to the extended state C2, forming a freely swingable fulcrum. The transition from state C1 to C2 may be performed by carrying out the transition process from state C1 to C2 after the horizontal extension of the direction control unit U by the transition from state Ca to Cb in step S2 of the flowchart in FIG. 5.

[0075] (6) Regarding the fulcrum structure, it was described that a concave portion is formed on the side of the direction control unit U and a convex portion is formed on the side of the lunar surface fixing unit D, and that a contact point for freely swinging is configured by the engagement of these uneven portions. However, the relationship between the uneven portions may be reversed.

[0076] (7) Regarding the fulcrum structure, if it is configured with the uneven shape shown and described, when the stabilization mechanism 60 (which can also function as a rotation stopper) in FIG. 13 is not provided, there is a possibility that the direction control unit U cannot be prevented from freely rotating around the horizontal plane. In order to prevent this free rotation around the horizontal plane, a fulcrum structure may be formed with a two-axis gimbal structure so that the balance posture of the direction control unit U is determined with two degrees of freedom in a state where there is no degree of freedom of rotation around the horizontal plane.

[0077] FIG. 17 is a diagram schematically showing a two-axis gimbal structure 100 that can be used for a fulcrum structure, and has a first rotation axis AX1 and a second rotation axis AX2 that are orthogonal to each other as main components. The first rotation axis AX1 rotatably connects the first rod R1 and the second rod R2 to each other, and the second rotation axis AX2 rotatably connects the second rod R2 and the third rod R3 to each other. (Note that in the state shown in the drawing where the two-axis gimbal structure 100 is not tilted, the first rod R1 extends in the vertical direction, the second rod R2 extends in the horizontal lateral direction, and the third rod R3 extends in the horizontal front-rear direction (perpendicular to the paper surface), and the three rods R1, R2, and R3 are arranged in a mutually orthogonal shape.) Here, the first rod R1 is configured to be fixed to the lunar surface fixing portion D, and the plane formed by the second rod R2 and the third rod R3 (the plane in the direction spanned by these two mutually perpendicular rods) is configured to be fixed to the pointing control unit U. By doing so, the pointing control unit U can rotate only by the rotation direction D1 by the first rotation axis AX1 and the rotation direction D2 by the second rotation axis AX2, (that is, the balance posture of the pointing control unit U has two degrees of freedom,) and rotation in the rotation direction D3 in the horizontal direction can be made impossible. (Note that the rotation direction D2 by the second rotation axis AX2 and the rotation direction D3 in the horizontal direction are exactly perpendicular to the paper surface. Since such directions D2 and D3 cannot be drawn in a cross-sectional view state, schematically, assuming a perspective view state, their rotation directions D2 and D3 are drawn, which is different from the two-axis gimbal structure 100 drawn in the cross-sectional view state.)

[0078] Regarding the fulcrum structure, it is also possible to use a combination of the two-axis gimbal structure 100 in FIG. 17 and the fixing mechanism / extension fixing release mechanism in FIG. 16. For each of the fulcrum structures related to such various combinations, any embodiment using or not using the stabilization mechanism 60 in FIG. 13 is possible.

Explanation of Signs

[0079] 10... Lunar orbiting station device (antenna pointing device) 1... Upper surface part, AT... Antenna part, 11... Fixing part, 12... Rotating part, 13, 14, 15... Receiving parts 2... Side housing part, 2U... Upper surface part 3... Central support part, 31, 32... Fulcrum parts 4…Bottom surface part 5…Leg part, 51…Length adjustment mechanism 6…Telescoping mechanism, 61, 71…Center side bearing parts, 62, 72…Rotating shaft parts, 63, 73…Outer peripheral side bearing parts 60…Stabilization mechanism, 64…Thread winding part, 65…Cable

Claims

1. An antenna pointing device comprising a physical oscillator mechanism, characterized in that an antenna unit is fixedly provided on the physical oscillator mechanism, and the pointing control of the antenna unit is realized according to the balance posture of the physical oscillator mechanism.

2. The antenna pointing device according to claim 1, further comprising equipment and a housing for storing the equipment, wherein the physical oscillator mechanism is configured to include at least a part of the housing for storing the equipment.

3. The balance posture is realized when a plurality of parts of the housing, which are included in the physical oscillator mechanism, move from a state where they are arranged on the center side to the outer peripheral side, respectively, so that the plurality of parts of the housing are arranged radially. The antenna pointing device according to claim 2, characterized in that it is realized.

4. The antenna pointing device according to claim 3, further comprising a telescopic mechanism for moving each of the plurality of parts of the housing between the center side and the outer peripheral side, and the length of the movement is adjustable, so that the balance posture is adjustable.

5. The antenna pointing device according to claim 4, characterized in that the telescopic mechanism includes a ball screw mechanism.

6. The antenna pointing device according to claim 4, further comprising a single drive mechanism for driving the telescopic mechanism, and the single drive mechanism is arranged on the center side, so that each of the plurality of parts of the housing can be moved by the single drive mechanism.

7. The antenna pointing device according to claim 1, characterized in that the fulcrum structure for enabling the physical oscillator mechanism to swing is configured as a two-axis gimbal.

8. The antenna pointing device according to claim 1, further comprising a fixing part for providing a fulcrum for the physical oscillator mechanism to swing, wherein the physical oscillator mechanism and the fixing part are in a pre-fixed state, and when the fixed state is released, the physical oscillator mechanism can swing. ​ ​ ​

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