Three-dimensional space craft and method for controlling the same

Abstract

To provide a three-dimensional space craft having a so-called tensegrity structure and capable of appropriately controlling vibration even if the vibration occurs when landing to work on a satellite or a planet upon reception of air resistance, a solar wind disturbance or the like.SOLUTION: A three-dimensional space craft 100 comprises a plurality of compression members 10 and a plurality of tension members 20. Three or more tension members 20 are connected to the end of each compression member 10. A three-dimensional shape formed by the compression members 10 and the tension members 20 is configured to be held by the tension of the tension members 20. A damping force variable damper 50 is installed in at least one of the compression and tension members 10 and 20. The damping force variable damper 50 is configured to generate a prescribed force in the longitudinal direction of the compression member 10 and the tension member 20.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a three-dimensional spacecraft and a control method thereof. [Background technology]

[0002] In the development of large space structures, lightweight structures that can be stored and deployed are required to reduce launch costs, and the application of tensegrity structures is expected. For example, the University of California is conducting research and development on a tensegrity structure robot for planetary exploration. This robot has a configuration in which the spatial arrangement of the compression members is changed by using a tension member length adjustment actuator to change the length of the tension members, allowing the robot to move by changing its center of gravity.

[0003] Patent Document 1 discloses a tensegrity robot that includes a plurality of compression members, a plurality of tension members, and a plurality of actuators, each of which is attached to one of the compression members and is configured to be able to selectively change the tension or length of the tension member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2023 / 0050299 Summary of the Invention [Problem to be solved by the invention]

[0005] Spacecraft that utilize tensegrity structures are lightweight and highly structurally stable, but like ordinary spacecraft, vibrations occur throughout the spacecraft when it is released from a rocket, when attitude control is performed using reaction wheels, or when it is subjected to air resistance or solar wind disturbances. When precision observation and measuring instruments are installed on a spacecraft with a tensegrity structure to observe natural phenomena in space or human activities on Earth, even slight vibrations must be suppressed.

[0006] Patent Document 1 does not clearly explain how to suppress vibrations that occur when the tensegrity robot moves or receives external force.

[0007] The purpose of the present disclosure is to appropriately damp vibrations in a three-dimensional spacecraft having a so-called tensegrity structure, even when the spacecraft vibrates when subjected to air resistance, solar wind disturbances, etc., or when it lands on a satellite or planet and performs work. [Means for solving the problem]

[0008] The three-dimensional spacecraft disclosed herein comprises a plurality of compression members and a plurality of tension members, with three or more tension members connected to each end of the compression members, and is configured so that the three-dimensional shape formed by the compression members and tension members is maintained by the tension of the tension members, and a variable damping force damper is installed in at least one of the compression members and tension members, and the variable damping force damper is configured to generate a predetermined force in the longitudinal direction of the compression member or tension member. [Effects of the Invention]

[0009] According to the present disclosure, even if a three-dimensional spacecraft having a so-called tensegrity structure vibrates when subjected to air resistance or solar wind disturbance, or when landing on a satellite or planet to perform work, the vibrations can be appropriately damped. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1 is a perspective view showing a three-dimensional spacecraft according to a first embodiment. [Figure 1B] FIG. 1B is a front view showing the three-dimensional spacecraft of FIG. 1A. [Figure 1C] FIG. 1B is a side view showing the three-dimensional spacecraft of FIG. 1A. [Figure 2] 1 is a cross-sectional view showing a variable damping force damper according to a first embodiment. [Figure 3] FIG. 1 is a block diagram of a three-dimensional spacecraft according to a first embodiment. [Figure 4] FIG. 2 is a flow chart showing a vibration damping process for a spacecraft with a three-dimensional structure according to the first embodiment. [Figure 5] FIG. 10 is a perspective view showing a three-dimensional spacecraft according to a second embodiment. [Figure 6] FIG. 10 is a cross-sectional view showing a variable damping force damper according to a second embodiment. [Figure 7] FIG. 11 is a perspective view showing a three-dimensional spacecraft according to a third embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing a tension member length control device according to a third embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing a variable damping force damper according to a third embodiment. [Figure 10] FIG. 10 is a perspective view showing a three-dimensional spacecraft according to a fourth embodiment. [Figure 11] FIG. 10 is a partial cross-sectional view showing a variable damping force damper according to a fourth embodiment. [Figure 12A] FIG. 1 is a schematic perspective view showing an example of a tensegrity structure. [Figure 12B] FIG. 12B is a diagram of a mechanical model of the tensegrity structure shown in FIG. 12A. [Figure 12C] FIG. 12B is a physical function diagram of the tensegrity structure shown in FIG. 12A. [Figure 12D] 1 is a table showing the meanings of symbols used in a physical function diagram; [Figure 13A] 1 is a schematic perspective view showing the configuration of a compression member, a tension member, and a variable damping force damper according to a first embodiment. FIG. [Figure 13B] FIG. 1 is a diagram showing a mechanical model of the first embodiment. [Figure 13C] FIG. 2 is a physical function diagram of the first embodiment. [Figure 14A] FIG. 12B is a physical function diagram that takes into account the motion of the tensegrity structure shown in FIG. 12A. [Figure 14B] 12B is a diagram showing a process of deriving the vibration transfer characteristics (transfer function) of the tensegrity structure shown in FIG. 12A. FIG. [Figure 15A] FIG. 1 is a physical function diagram taking into consideration the exercise of the first embodiment. [Figure 15B] 4 is a diagram showing a process of deriving the vibration transfer characteristic (transfer function) of Example 1. FIG. [Figure 16A] 12B is a graph showing vibration transmission characteristics in the mechanical model of the tensegrity structure shown in FIG. 12A. [Figure 16B] 12B is a graph showing vibration transmission characteristics in the mechanical model of the tensegrity structure shown in FIG. 12A. [Figure 17A] 4 is a graph showing vibration transmission characteristics in the dynamic model of Example 1. [Figure 17B] 4 is a graph showing vibration transmission characteristics in the dynamic model of Example 1. [Figure 18A] FIG. 10 is a schematic perspective view showing the configuration of a compression member, a tension member, and a variable damping force damper according to a fourth embodiment. [Figure 18B] FIG. 10 is a diagram showing a mechanical model of Example 4. [Figure 18C] FIG. 10 is a physical function diagram of the fourth embodiment. [Figure 18D] FIG. 10 is a diagram showing a process of deriving the vibration transfer characteristic (transfer function) in Example 4. [Figure 19A] 10 is a graph showing vibration transmission characteristics in the dynamic model of Example 4. [Figure 19B] 10 is a graph showing vibration transmission characteristics in the dynamic model of Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [Example]

[0012] FIG. 1A is a perspective view showing a three-dimensional spacecraft according to a first embodiment.

[0013] In this figure, a three-dimensional spacecraft 100 comprises a plurality of compression members 10, a plurality of tension members 20, a plurality of poles 30, a housing 40, and a plurality of variable damping force dampers 50. The compression members 10 and tension members 20, which are the main components, form a tensegrity structure. The tension members 20 are connected to the ends of the compression members 10. The distance between these ends is kept constant by the tension members 20. Poles 30 are connected to each side of the housing 40. Each pole 30 supports a different compression member 10 that is adjacent to it.

[0014] Variable damping force dampers 50 are installed at the ends of the compression member 10. In other words, variable damping force dampers 50 are attached to both ends of the tension member 20, and the tension member 20 is connected to the compression member 10 via the variable damping force dampers 50. The tension member 20 is configured so that the distance from the end of the compression member 10 can be changed within a predetermined range by the variable damping force dampers 50.

[0015] FIG. 1B is a front view of the three-dimensional spacecraft shown in FIG. 1A.

[0016] As shown in FIG. 1B, multiple variable damping dampers 50 are attached to each end of the horizontal compression members 10. One end of a tension member 20 is attached to each of the multiple variable damping dampers 50. The other end of the tension member 20 is attached to a variable damping damper 50 attached to another compression member 10. This keeps the distance between the ends of the two compression members 10 constant. The two compression members 10 are also erected vertically.

[0017] FIG. 1C is a side view of the three-dimensional spacecraft shown in FIG. 1A.

[0018] As shown in FIG. 1C, a plurality of variable damping force dampers 50 are also attached to each end of the vertical compression member 10.

[0019] The compression member 10 is formed, for example, from a component combining beryllium copper, carbon fiber reinforced plastics (CFRP), and a copper alloy. Because the compression member 10 is used as a deployable dipole antenna, it is desirable to use a material suitable for this purpose. The tension member 20 is formed, for example, from a resin line such as polyethylene (similar to fishing line), a wire made of CFRP, stainless steel, or a copper alloy, or a thin film of resin, CFRP, stainless steel, copper alloy, or the like. The pole 30 is formed, for example, from beryllium copper, stainless steel, or the like.

[0020] In this way, the vertical compression members 10 and the horizontal compression members 10 are not in direct contact with each other, and tension is applied to the tension members 20, so that the three-dimensional spacecraft 100 is configured to maintain a predetermined shape.

[0021] FIG. 2 is a cross-sectional view showing the variable damping force damper of this embodiment.

[0022] In this figure, the variable damping force damper 50 has a coil 52, an iron core 54, an outer tube 56, and a latch 58. The coil 52 and the iron core 54 are housed in the outer tube 56. The latch 58 is installed inside the outer tube 56 and enables the iron core 54 to be fixed in place. An end of the tension member 20 is connected to the iron core 54. The outer tube 56 is fixed to the compression member 10. The compression member 10 is provided with wiring that supplies current 15 to the coil 52.

[0023] FIG. 3 is a block diagram of the three-dimensional spacecraft of this embodiment.

[0024] This figure shows a compression member 10, a tension member 20, a housing 40, and a variable damping force damper 50 that constitute a three-dimensional spacecraft. The housing 40 has a control device 60 (control unit), an attitude detection device 42 (attitude detection unit), an attitude control device 44 (attitude control unit), and a variable load device 46 (variable load unit). The control device 60 has a tension detector 62, an ideal damping force calculation device 64 (ideal damping force calculation unit), and an output section 66.

[0025] When the three-dimensional spacecraft vibrates, the tension of the tension member 20 changes, causing the iron core of the damping-force variable damper 50 to move. This movement generates a current in the coil of the damping-force variable damper 50. The tension detector 62 detects this current, calculates the tension value, and transmits it to the ideal damping force calculation device 64. The ideal damping force calculation device 64 also receives data related to the attitude of the three-dimensional spacecraft from the attitude detection device 42. The ideal damping force calculation device 64 uses the tension value and the data related to the attitude to calculate the ideal damping force and ideal attitude, and transmits the data to the output unit 66. Here, the ideal damping force refers to the optimal damping force for controlling the change in the tension of the tension member 20 due to the vibration of the three-dimensional spacecraft. The ideal attitude refers to the shape and orientation of the three-dimensional spacecraft that are optimal for the operations performed by the three-dimensional spacecraft. To maintain this attitude, the tension and length of the tension member 20 are adjusted. Furthermore, the latch 58 is normally in an open state, and when the length of the tension member 20 is fixed, the latch 58 is used to fix the iron core 54.

[0026] The output unit 66 uses the data on the ideal damping force and ideal attitude to calculate at least one of the current and voltage used to control the damping-force variable damper 50 and transmits it to the variable load device 46. The variable load device 46 transmits data related to the damping force (velocity) to the damping-force variable damper 50. The output unit 66 also transmits data related to the attitude of the three-dimensional spacecraft to the attitude control device 44. The damping-force variable damper 50 generates a compressive force to be applied to the compression member 10 based on the data related to the damping force (velocity) received from the variable load device 46. The damping-force variable damper 50 may also change the current in the coil to adjust the tension of the tension member 20 based on the data.

[0027] Alternatively, a strain gauge may be installed on the tension member to detect the tension of the tension member. In this case, the current or voltage signal obtained by the strain gauge is received by the tension detector 62, and the tension value is calculated.

[0028] FIG. 4 is a flow chart showing a vibration suppression process (control method) for a spacecraft with a three-dimensional structure according to this embodiment.

[0029] In this figure, the three-dimensional spacecraft is an artificial satellite.

[0030] When a disturbance causes the satellite to vibrate (step S110), vibrations (slight expansion and contraction) occur in the tension member, causing a change in the tension of the tension member (step S120). The change in tension causes the iron core of the variable damping force damper to move a small distance (step S130). Note that forces such as gravity and centrifugal force acting on the iron core are smaller than the tension. In the variable damping force damper, the movement of the iron core generates an electromagnetically induced electromotive force in the coil, causing a current to flow through the coil (step S140). The current flowing through the coil is transmitted to a control device in the housing via wiring attached to the compression member and the pole. The control device then detects the current and calculates a damping force corresponding to the tension or the change in tension (step S150). The output unit included in the control device then adjusts the variable load (damping force) (step S160). That is, a current that generates an electromagnetic force corresponding to the calculated damping force is passed through the coil of the variable damping force damper, thereby adjusting the electromagnetic force acting on the iron core.

[0031] Although this specification describes a case where the damping force that suppresses vibrations of the compression or tension members of a three-dimensional spacecraft is an electromagnetic force acting between a coil and an iron core, the configuration for generating forces such as damping forces in a three-dimensional spacecraft according to the present disclosure is not limited to this. Furthermore, in addition to the damping force, for example, electromagnetic forces may be adjusted to maintain the overall shape, attitude, etc. of the three-dimensional spacecraft. Therefore, these forces such as damping forces may be collectively referred to as "predetermined forces" in this specification.

[0032] In summary, in the control method for a three-dimensional spacecraft, the control device detects a change in current or voltage in the variable damping force damper, calculates a damping force that is a predetermined force for controlling vibration, and applies a current or voltage corresponding to the damping force to the variable damping force damper. Furthermore, the control device determines whether the change in current or voltage has decreased.

[0033] Next, it is determined whether the vibration of the tension member has damped based on the change in current or voltage (step S170). If the vibration has damped sufficiently, the iron core may be fixed using a latch to fix the position of the end of the tension member (step S180). In other words, the length of the portion of the tension member exposed from the outer tube of the damping-force variable damper may be fixed. On the other hand, if the vibration has not damped sufficiently, the process returns to step S160 and adjusts the variable load.

[0034] By carrying out the above steps, even if the satellite vibrates due to disturbances, the vibrations can be properly damped, thereby maintaining the shape, orbit, etc. of the satellite and preventing damage to satellite parts, etc.

[0035] Furthermore, even when a spacecraft lands on a satellite such as the moon or a planet such as Mars to perform work, if the spacecraft vibrates due to movement, collision, etc., the vibrations can be damped, the shape of the spacecraft can be maintained, and the spacecraft can continue to move, work, etc. Furthermore, damage to spacecraft parts can be prevented. [Example]

[0036] In the description of this embodiment, only the differences from the first embodiment will be explained.

[0037] FIG. 5 is a perspective view showing a three-dimensional spacecraft according to the second embodiment.

[0038] In the three-dimensional spacecraft 500 shown in this figure, the damping force variable damper 150 is longer than in the first embodiment.

[0039] FIG. 6 is a cross-sectional view showing a variable damping force damper according to a second embodiment.

[0040] As shown in this figure, the variable damping force damper 150 has a coil 152, an iron core 154, an outer cylinder 156, and a latch 158. A plurality of latches 158 are installed at equal intervals inside the outer cylinder 156. The coil 152 is arranged between adjacent latches 158. The coil 152 may be arranged in sections. The overall length of the coil 152 is longer than in the first embodiment. In other words, the overall length of the variable damping force damper 150 is longer than in the first embodiment. The iron core 154 can be fixed in a predetermined position by any of the plurality of latches 158. The outer cylinder 156 is fixed to the compression member 10. The compression member 10 is provided with wiring that supplies current 15 to the coil 152.

[0041] According to this embodiment, the movable range of the iron core 154 can be increased. Also, the length of the portion of the tension member 20 that can be housed in the outer tube 156 can be increased, and the range over which the length of the sides of the three-dimensional spacecraft 500 formed by the tension member 20 can be adjusted can be increased. This increases the range over which the shape of the three-dimensional spacecraft 500 can be adjusted. Also, the adjustable range of the damping force can be increased. [Example]

[0042] In the description of this embodiment, only the differences from the first embodiment will be explained.

[0043] FIG. 7 is a perspective view showing a spacecraft with a three-dimensional structure according to a third embodiment.

[0044] In this figure, the variable damping force damper 250 of the three-dimensional spacecraft 700 is installed closer to the center rather than at the end of the tension member 20. A tension member length control device 270 (tension member length control unit) is installed at the end of the compression member 10.

[0045] FIG. 8 is a cross-sectional view showing the tension member length control device of this embodiment.

[0046] As shown in this figure, the tension member length control device 270 includes a control unit 772, a motor 774, and a tension member take-up unit 776. The tension member length control device 270 is attached to the end of the compression member 10. The tension member connected to the tension member take-up unit 776 is configured so that the length of the exposed portion can be adjusted by rotating the motor 774.

[0047] FIG. 9 is a cross-sectional view showing the variable damping force damper of this embodiment.

[0048] In this figure, the variable damping force damper 250 has a coil 752, an iron core 754, an outer tube 756, and a latch 758. The coil 752 and the iron core 754 are housed in the outer tube 756. The latch 758 is installed inside the outer tube 756 and enables the iron core 754 to be fixed in a predetermined position. An end of the tension member 20 is connected to the iron core 754. The outer tube 756 is fixed to a damper support portion of a tension member take-up portion 776 provided at the end of the compression member 10. The compression member 10 is provided with wiring that supplies current 15 to the coil 752.

[0049] According to this embodiment, the effective length of the tension member 20 can be adjusted. [Example]

[0050] In the description of this embodiment, only the differences from the first embodiment will be explained.

[0051] FIG. 10 is a perspective view showing the three-dimensional spacecraft of this embodiment.

[0052] In this figure, a variable damping force damper 350 of a three-dimensional spacecraft 1000 is supported by a pole 330 provided on a housing 40. The variable damping force damper 350 is installed between two compression members, i.e., iron core / compression members 1054, arranged in series. The iron core / compression members 1054 are connected to both ends of the variable damping force damper 350. An end of a tension member 20 is connected to the other exposed end of the iron core / compression member 1054.

[0053] FIG. 11 is a partial cross-sectional view showing the variable damping force damper of this embodiment.

[0054] This figure shows the right side of the damping-force variable damper 350. The damping-force variable damper 350 has a coil 1052, an iron core / compression member 1054, an outer cylinder 1056, and a latch 1058. The coil 1052 and one end of the iron core / compression member 1054 are housed in the outer cylinder 1056. The latch 1058 is installed inside the outer cylinder 1056 and enables the iron core / compression member 1054 to be fixed in a predetermined position. Wiring that supplies current 15 to the coil 1052 is provided on the pole 330.

[0055] When the spacecraft vibrates due to disturbances, the iron core / compression member 1054 moves a small distance. In the damping-force variable damper 350, the movement of the iron core / compression member 1054 generates an electromagnetically induced electromotive force in the coil 1052, which causes a current 15 to flow in the coil 1052. The current 15 flowing in the coil 1052 is transmitted to the control device in the housing 40 via wiring provided on the pole 330. The control device then detects the current 15 and calculates the damping force according to the force acting on the iron core / compression member 1054. The variable load (damping force) is then adjusted using an output unit included in the control device.

[0056] Therefore, in this embodiment, the damping force can be adjusted in the same manner as in the vibration damping process of the three-dimensional spacecraft of FIG. 4 (embodiment 1).

[0057] In this way, the variable damping force damper 350 may be installed at a location other than the end of the compression member 10 or the tension member 20.

[0058] According to this embodiment, the length of the sides of the three-dimensional spacecraft 1000 can be adjusted not on the tension member 20 side but on the iron core / compression member 1054 side.

[0059] Next, an example of a numerical calculation performed by converting the structure of the three-dimensional spacecraft according to the present disclosure into a dynamic model will be described.

[0060] (Example of numerical calculation using a mechanical model) First, an example of a tensegrity structure will be described.

[0061] FIG. 12A is a schematic perspective view showing the configuration of a compression member and a tension member of an example tensegrity structure.

[0062] This figure shows a three-dimensional model having a compression member 10 and a tension member 20, but without a variable damping force damper. The compression member 10 is arranged vertically in the figure. Three tension members 20 are attached to one end of the compression member 10.

[0063] FIG. 12B is a diagram of a mechanical model of the tensegrity structure shown in FIG. 12A.

[0064] In this figure, a spring K and a damper C are connected in parallel to a mass point M. This figure is a mechanical model corresponding to FIG. 12A.

[0065] FIG. 12C is a physical function diagram of the tensegrity structure shown in FIG. 12A.

[0066] In this figure, an external force f is applied to the mass point M of the mechanical model in Figure 12B. in When the force is applied, the velocity v of the mass M and the damping force f out The function for estimating the value of is shown in the figure.

[0067] The spring force proportional to the change in length of the tension member corresponds to K, and the damping force proportional to the change in length of the tension member over time corresponds to f out C corresponds to the damping force f. The tension member is assumed to be given an appropriate initial tension in the equilibrium state, and the condition is set so that no sagging occurs in the tension member. out is generated based on the velocity v of the mass M.

[0068] FIG. 12D is a table showing the meanings of symbols used in the physical function diagram.

[0069] In this diagram, the symbols used in the physical function diagram correspond to the operations of multiplication, summation, branch (equal sign), inversion, and integration, respectively.

[0070] Next, a first embodiment will be described.

[0071] FIG. 13A is a schematic perspective view showing the configuration of a compression member, a tension member, and a damping-force variable damper according to the first embodiment.

[0072] This figure shows a three-dimensional model having a compression member 10, a tension member 20, and a variable damping force damper 50. The arrangement of the compression member 10 and the tension member 20 is similar to that of the tensegrity structure shown in FIG. 12A. The variable damping force damper 50 is attached to the end of the tension member 20.

[0073] FIG. 13B is a diagram of a mechanical model of the first embodiment.

[0074] In this figure, in addition to the tensegrity structure configuration shown in Fig. 12B, a damper D (variable damping force damper 50) is connected in series to a spring K. Fig. 13B is a mechanical model corresponding to Fig. 13A.

[0075] FIG. 13C is a physical function diagram of the first embodiment.

[0076] In this figure, a damper D is added to the tensegrity structure configuration shown in Fig. 12C. The damping force of the damper D is generated based on the tension of the tension member.

[0077] FIG. 14A is a physical function diagram that takes into account the motion of the tensegrity structure shown in FIG. 12A.

[0078] This figure is the same physical function diagram as FIG. 12C, but is shown using functions including differential and integral functions.

[0079] In FIG. 14A, the time derivative of velocity v (v dots) and the time derivative of force f (f dots) are shown.

[0080] FIG. 14B is a diagram showing a process of deriving the vibration transfer characteristics (transfer function) of the tensegrity structure shown in FIG. 12A.

[0081] In this figure, Equation (1) expresses the configuration of FIG. 14A as a differential simultaneous equation. Equation (2) expresses Equation (1) as a matrix. Equation (3) is the transfer function G obtained by converting Equation (2).

[0082] FIG. 15A is a physical function diagram taking into account the exercise of the first embodiment.

[0083] This figure, like FIG. 14A, is illustrated using functions including differential and integral functions.

[0084] FIG. 15B is a diagram illustrating a process of deriving the transfer function in the first embodiment.

[0085] In this figure, Equation (4) is a differential simultaneous equation expressed as a matrix, and Equation (5) is the transfer function G obtained by converting Equation (4).

[0086] Fig. 16A is a graph showing the vibration transmission characteristics of the mechanical model of the tensegrity structure shown in Fig. 12A. The horizontal axis represents the normalized frequency ω / ω0, and the vertical axis represents the vibration transmissibility (Force Transmissibility).

[0087] In this figure, C = 0, which is the condition where no damping force is applied. Therefore, when ω is equal to the resonance frequency ω0, that is, when ω / ω0 = 1, the vibration transmissibility becomes infinite and diverges.

[0088] FIG. 16B is a graph showing vibration transmission characteristics in the mechanical model of the tensegrity structure shown in FIG. 12A.

[0089] In this figure, C=1, which is the condition under which damping force is applied. Therefore, even when ω is equal to the resonance frequency ω0, the vibration transmissibility remains at a predetermined value without diverging.

[0090] FIG. 17A is a graph showing vibration transmission characteristics in the mechanical model of Example 1.

[0091] In this figure, C = 0, but D = 1, which is the condition under which the damping force of the variable damper installed on the tension member is applied. Therefore, even when ω is equal to the resonant frequency ω0, the vibration transmissibility remains at the specified value without diverging.

[0092] FIG. 17B is a graph showing the vibration transmission characteristics in the mechanical model of Example 1.

[0093] In this figure, C=1 and D=1, which are the conditions under which two damping forces are applied. Therefore, even when ω is equal to the resonant frequency ω0, the vibration transmissibility remains at a specified value without diverging. In addition, the force transmissibility is negative (-6 dB or less) for all frequencies. Therefore, even in the low-frequency region (ω / ω0≦1), the damping force can be controlled and vibration can be suppressed.

[0094] Next, a fourth embodiment will be described.

[0095] FIG. 18A is a schematic perspective view showing the arrangement of compression members and tension members in Example 4. FIG.

[0096] This figure shows a three-dimensional model having a compression member 10, a tension member 20, and a variable damping force damper 50. The arrangement of the compression member 10 and the tension member 20 is similar to that of the tensegrity structure shown in FIG. 12A. The variable damping force damper 50 is attached to the compression member 10.

[0097] FIG. 18B is a diagram of a mechanical model of Example 4.

[0098] In this figure, in addition to the configuration of the tensegrity structure shown in Fig. 12B, in which a spring K and a damper C are connected in parallel to a mass point M, a damper D (a variable damping force damper 50) is connected in series to the mass point M. Fig. 18B is a mechanical model corresponding to Fig. 18A.

[0099] FIG. 18C is a physical function diagram of the fourth embodiment.

[0100] In this figure, a damper C' is provided instead of the damper C, which is a component of the comparative example shown in Figure 12C. Here, C' is a configuration in which dampers C and D are connected in series, and is expressed as C' = C + D. The damping force of damper D is generated based on the tension of the tension member.

[0101] FIG. 18D is a diagram showing the process of deriving the vibration transfer characteristic (transfer function) in Example 4.

[0102] In this figure, Equation (6) expresses the configuration of FIG. 18C as a differential simultaneous equation. Equation (7) expresses Equation (6) as a matrix. Equation (8) is the transfer function G obtained by converting Equation (7).

[0103] FIG. 19A is a graph showing vibration transmission characteristics in the mechanical model of Example 4.

[0104] In this figure, C = 0, but D = 1, which is the condition under which the damping force of the variable damper installed in the compression member is applied. Therefore, even when ω is equal to the resonant frequency ω0, the vibration transmissibility remains at the specified value without diverging.

[0105] FIG. 19B is a graph showing the vibration transmission characteristics in the mechanical model of Example 4.

[0106] In this figure, C=1 and D=1, which are the conditions under which two damping forces are applied. Therefore, even when ω is equal to the resonant frequency ω0, the vibration transmissibility remains a negative value (-6 dB or less) without diverging. Furthermore, the vibration transmissibility is 0 dB or less for all frequencies. Therefore, even in the low-frequency region (ω / ω0≦1), the damping force can be controlled and vibration can be suppressed.

[0107] Preferred embodiments of the three-dimensional spacecraft according to the present disclosure will be described below.

[0108] The compression member has a structure that can be collapsed by releasing the tension member and can be expanded to its original three-dimensional structure by tensioning the tension member.

[0109] The compression member is preferably made of a dielectric material and functions as an observation device (for example, an antenna).

[0110] When a thin film is used as the tension member, an array antenna or a solar panel is attached to the surface of the thin film.

[0111] The variable damping force damper may be, for example, an electromagnetic shunt damper, a ball screw type electromagnetic damper, a magnetic fluid damper, a piezoelectric damper, or the like.

[0112] The latch is preferably a mechanical anti-strain relief stop.

[0113] The compression and tension members are preferably symmetrically positioned to enhance the stability of the structure.

[0114] The damping force of the variable damping force damper can be changed over time.

[0115] The damping force of the variable damping force damper is changed by using a variable load unit to change, for example, a resistance value.

[0116] The energy of vibrations generated in the variable damping force damper may be converted into electricity and stored in a secondary battery. [Explanation of symbols]

[0117] 10: compression member, 15: current, 20: tension member, 30, 330: pole, 40: housing, 42: attitude detection device, 44: attitude control device, 46: variable load device, 50, 150, 250, 350: damping force variable damper, 52, 152, 752, 1052: coil, 54, 154, 754: iron core, 56, 156, 756, 1056: outer cylinder, 58, 158, 758, 1058: latch, 60: control device, 62: tension detector, 64: ideal damping force calculation device, 66: output unit, 100, 500, 700, 1000: three-dimensional structure spacecraft, 270: tension member length control device, 772: control unit, 774: motor, 776: tension member winding unit, 1054: iron core and compression member.

Claims

1. a plurality of compression members; a plurality of tension members; Three or more of the tension members are connected to each end of the compression member; a three-dimensional shape formed by the compression member and the tension member is maintained by tension of the tension member; a variable damping force damper is provided on at least one of the compression member and the tension member; The variable damping force damper is configured to generate a predetermined force in the longitudinal direction of the compression member or the tension member.

2. 2. The spacecraft according to claim 1, wherein the predetermined force includes a damping force that suppresses vibration of the compression member or the tension member.

3. 2. The spacecraft according to claim 1, wherein the variable damping force damper is installed at an end of the compression member or the tension member.

4. 2. The spacecraft according to claim 1, wherein the variable damping force damper is installed at a location other than an end of the compression member or the tension member.

5. The housing and a pole attached to the housing, 2. The spacecraft according to claim 1, wherein the variable damping force damper is installed between two of the compression members arranged in series and connected to the pole.

6. the variable damping force damper has a coil, 2. The spacecraft according to claim 1, wherein the coil has an iron core, or an iron core / compression member, inserted therein, the iron core being disposed in the compression member or the tension member.

7. The variable damping force damper further includes a latch, 7. The spacecraft of claim 6, wherein the latch secures the core or the core / compression member in place.

8. The device further includes a tension detector, a posture detection unit, an ideal damping force calculation unit, an output unit, and a variable load unit, the tension detector detects a current generated in the coil of the damping force variable damper and calculates a value of the tension of the tension member; the ideal damping force calculation unit receives data relating to the attitude of the three-dimensional spacecraft from the attitude detection unit, and calculates an ideal damping force and an ideal attitude using the tension value and the data relating to the attitude; the output unit calculates at least one of a current and a voltage used to control the damping force variable damper using data on the ideal damping force and the ideal posture; 7. The spacecraft according to claim 6, wherein the variable load unit transmits data relating to the damping force to the variable damper.

9. The latch is provided in a plurality of pieces, 8. The spacecraft according to claim 7, wherein the coil is disposed between adjacent latches.

10. The spacecraft according to claim 1 , further comprising a tension member length control unit that adjusts the length of the exposed portion of the tension member.

11. 2. The spacecraft according to claim 1, wherein said compression member is formed of a component made of beryllium copper or a combination of carbon fiber reinforced plastic and copper alloy.

12. 2. The spacecraft according to claim 1, wherein said tension members are formed of wires or thin films made of resin, carbon fiber reinforced plastic, stainless steel, or copper alloy.

13. 6. The spacecraft according to claim 5, wherein said pole is made of beryllium copper or stainless steel.

14. a plurality of compression members; a plurality of tension members; Three or more of the tension members are connected to each end of the compression member; a three-dimensional shape formed by the compression member and the tension member is maintained by tension of the tension member; a variable damping force damper is provided on at least one of the compression member and the tension member; a method for controlling a three-dimensional spacecraft, wherein the variable damping force damper is configured to generate a predetermined force in a longitudinal direction of the compression member or the tension member, The control device detecting a change in current or voltage in the damping force variable damper, and calculating a damping force that is the predetermined force that reduces the change in the current or the voltage; a control method for a three-dimensional spacecraft, the current or the voltage corresponding to the damping force being applied to the variable damping force damper;

15. The method of claim 14 , wherein the controller determines whether the change in the current or the voltage has decreased.

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