JP2002070156A - Shape control method for variable-shape truss structural body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape control method for a variable-shape truss structural body capable of reducing the driving force required for expanding/ shrinking individual actuators and miniaturizing the actuators. SOLUTION: Avariable-shape truss frame 2 comprises quadrilateral basic trusses 4 connected into a ladder shape. Each basic truss 4 comprises a pair of upper and lower chord members 6, a pair of struts 8, and a diagonal member 10 diagonally provided along the diagonal line of the basic truss 4. The chord members 6, struts 8, and diagonal member 10 are rotatably connected together via hinge pins 12. The chord members 6 and the diagonal member 10 are formed with a fixed-length truss member having a fixed length, and the struts 8 are formed with expansible actuators A1 through A12. When the actuators are to be expanded, they are expanded in sequence starting from the actuator A1 farthest from a support end, thereby the moment for impeding the expansion of the actuators near the support end can be reduced, and the actuators A2 through A12 can be expanded with the minimum driving force required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling the shape of a variable-shaped truss structure which includes a plurality of telescoping truss members constituted by telescopic actuators and changes the shape by the expansion and contraction of each actuator.

[0002]

2. Description of the Related Art Conventionally, a variable-shaped truss (VGT:
Variable Geometry Truss) structures are known. In this variable shape truss structure, an actuator is incorporated in a part of a truss member constituting a triangular basic truss, and the shape is appropriately changed by expansion and contraction of the actuator. The actuators are incorporated at a plurality of locations and are individually controlled so that the entire structure is variously deformed into various shapes. For this reason, the deformable truss structure includes a movable or openable roof frame, a music hall stage, a movable sound insulating plate, a movable deck or a movable wall,
It is expected to be applied to movable solar panels and monuments that move in harmony with nature.

[0003]

In this variable-shaped truss structure, a supporting force acts on each truss member to support the structure. Therefore, when each actuator is extended or contracted, a driving force opposing such a supporting force must be applied to each actuator.

FIG. 7 (a) shows a cantilever-type variable-shaped truss structure 2 having one end fixedly supported on a wall 1. As shown in FIG. The variable-shaped truss structure 2 is configured by connecting quadrangular basic trusses 4 in a ladder shape. Each basic truss 4 is composed of a pair of upper and lower chords 6, a pair of bundles 8, and a diagonally arranged diagonally along a diagonal line from an intersection of one of the chords 6 and the bundle 8 to an intersection of the opposite side. It consists of 10.
The intersections of the chord members 6, the bundle members 8, and the diagonal members 10 are rotatably connected via hinge pins 12, respectively. The chord member 6 and the diagonal member 10 are members having a fixed length and a fixed length.
On the other hand, each bundle 8 is constituted by a telescopic actuator, and is a telescopic truss member. In FIG. 7A, the actuator of each bundle 8 is in a contracted state.

[0005] Here, it is assumed that all the actuators are extended to bring all the quadrilateral basic trusses into a small folded state as shown in FIG. 7 (b). Each bundle 8 has
A moment corresponding to the distance from the support end of the truss structure 2 acts. That is, a large moment acts on the bundle near the support end, and a small moment acts on the bundle far from the support end. In order to expand and contract each actuator, it is necessary to apply a sufficient driving force to overcome such a moment. In such a case, if each actuator is driven without considering the distance from the support end as shown in FIG. 7C, the actuator far from the support end can expand and contract with a small driving force, whereas the actuator far from the support end can expand and contract. Large actuators require a large driving force for expansion and contraction. As for the actuator close to the supporting end, a large-sized actuator capable of obtaining a sufficiently large driving force must be used from a design point of view, resulting in an increase in size, weight, and construction cost of the entire structure.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a variable-shaped truss structure capable of reducing the necessary driving force when each actuator is expanded and contracted, and An object of the present invention is to provide a method of controlling the shape of a variable-shaped truss structure that can be downsized.

[0007]

In order to achieve the above object, a method of controlling the shape of a variable-shaped truss structure according to the first aspect of the present invention comprises a plurality of telescoping truss members constituted by telescopic actuators. A method for controlling a variable shape truss structure that changes its shape by expansion and contraction of each actuator to a target shape, wherein a target expansion and contraction amount of each actuator for realizing the target shape is obtained, and one actuator is If the force acting in the direction that hinders the expansion and contraction of the one actuator decreases due to the own weight of the truss structure by expanding and contracting the other actuator in advance, the expansion and contraction of the other actuator may be reduced. The expansion / contraction drive order of each actuator is determined prior to the expansion / contraction of the one actuator, and each actuator is driven in accordance with this expansion / contraction drive order. Wherein the expanding and contracting toward the Yueta the target expansion amount of each.

According to a second aspect of the present invention, there is provided a method for controlling the shape of a variable-shaped truss structure, comprising a plurality of telescoping truss members constituted by telescopic actuators, and changing the shape by the expansion and contraction of each actuator. A method for controlling the shape of a variable-shaped truss structure having one end fixed, wherein, prior to one actuator, another actuator located on the distal end side of the truss structure with respect to the one actuator is expanded and contracted. Thereby, when the force acting in the direction that hinders the expansion and contraction of the one actuator decreases due to the weight of the truss structure, the other actuator is expanded and contracted prior to the one actuator. .

In these control methods, each actuator is driven to expand and contract in such an order that the force acting in a direction that hinders expansion and contraction of the actuator is reduced. Therefore, when the actuator is expanded and contracted, it is necessary to expand and contract the actuator. A small driving force is required and a large actuator capable of obtaining a large driving force is not required.
Therefore, it is possible to reduce the size of the entire actuator, and it is not necessary to increase the size, weight, and construction cost of the entire structure.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for controlling the shape of a variable shape truss structure according to the present invention will be described below. FIGS. 1A to 1E show a shape control procedure when the shape control method according to the present invention is applied to a cantilever-type variable shape truss structure.

The variable truss frame is the same as that shown in FIG.
Quadrilateral basic truss 4
Each of the basic trusses 4 is composed of a pair of upper and lower chord members 6, a pair of left and right bundle members, and a diagonally interposed diagonal line in the square basic truss 4 along the diagonal line. And material 10. Each string member 6, each bundle member 8 and each diagonal member 10 are rotatably connected to each other via hinge pins 12, respectively.
The chord member 6 and the diagonal member 10 are constituted by fixed-length truss members having a fixed length, while each bundle member 8 is constituted by an extensible actuator A1 to A12 as an extensible truss member. In FIG. 1A, each of the actuators A1 to A1
2 are all contracted.

Here, all the actuators A1 to A1
2 is extended to bring all the quadrangular basic trusses 4 into a small folded state as shown in FIG. 1 (e), and the entire deformable truss structure is brought into a contracted state. Here, the target expansion / contraction amount of each actuator for changing from the state shown in FIG. 1A to the state shown in FIG. 1E is obtained.

In the present invention, by expanding and contracting another actuator prior to one actuator,
When the force acting in the direction that hinders the expansion and contraction of one actuator decreases due to the weight of the truss structure, the expansion and contraction drive order of each actuator is adjusted so that the expansion and contraction of the other actuator precedes the expansion and contraction of the one actuator. Then, each actuator is expanded and contracted toward each target expansion and contraction amount in accordance with the expansion and contraction drive order. In other words, in the present embodiment, the actuator farthest from the support end is extended before the actuator closer to the support end, thereby acting on the actuator near the support end and hindering the extension. Therefore, the actuator is extended from the actuator farthest from the support end in order. In the following, the actuator A1 furthest from the support end will be referred to as a first actuator, and the actuators A2 to A12 closer to the support end will be referred to as second to twelfth actuators, respectively, in order of decreasing distance.

FIGS. 1 (b) to 1 (d) show an intermediate course when the actuator is extended in order from the actuator farthest from the support end. As shown in FIG. 1 (b), when the first and second actuators A1 and A2 are extended, the distal end portion of the truss structure 2 is contracted, and the third to twelfth actuators A3 closer to the support end than these. ~ A1
The moment acting on 2 decreases. Here the third-
When extending the fifth actuators A3 to A5, the third to fifth actuators A3 to A5 can be extended with a minimum necessary driving force. FIG. 1 (c) shows the third
The state when the fifth to fifth actuators A3 to A5 are extended is shown. Further, the sixth to eighth actuators A6 to A8 are extended as shown in FIG. Since the truss structure is sequentially contracted from the distal end by sequentially extending the actuators farthest from the support end in this manner, the moment acting on the actuators near the support end is also gradually reduced. In order to extend the shaft, a minimum necessary driving force is required. For this reason, a large actuator capable of outputting a large driving force is not required, and it is possible to avoid an increase in the size, weight, and construction cost of the entire structure.

Next, a case where the shape control method according to the present invention is applied to another type of variable shape truss structure will be described. FIG. 2 shows this variable-shaped truss structure. The variable-shaped truss structure 20 is a cantilever-type variable-shaped truss structure having one end fixedly supported on the ground 21, and a triangular fixed truss 22 and a quadrilateral variable truss 24 are alternately provided. It is configured. The triangular fixed truss 22 has three side members 28 rotatably connected to each other via a pin hinge 26. Further, the four fixed trusses 22 located at the center are provided with two side materials 28 so as to bisect the triangle of the fixed truss 22.
Is connected to the center of the remaining other sap 28, and one auxiliary member 30 is provided. These fixed trusses 2
2 are rotatably connected to each other via a pin hinge 26.

On the other hand, the quadrilateral variable truss 24 has four sap members 28 and 32 connected to each other via a pin hinge 26 so as to be rotatable, and a diagonal line connecting these intersections. And a stretchable variable length member 34 interposed along. Two of the four sap members 28 and 32 are shared with the adjacent fixed truss 22. The variable length member 34 is a telescopic actuator A1.
The variable truss 24 having the shape of a quadrilateral is folded and unfolded like a pantograph. In the state of FIG. 2, the entire structure is inclined leftward in the figure in a state where all the actuators are extended and all the variable trusses are folded and contracted to a small extent. When all the actuators are contracted and all the variable trusses are deployed, as shown in FIG. 6 (M), the entire structure falls into the right side in the figure.

A description will be given of a case where such a variable-shaped truss structure as a whole is deformed from the state shown in FIG. 2 to the state shown in FIG. 6 (M). As in the case described above, first, FIG.
The target expansion / contraction amount of each of the actuators A1 to A5 for changing the state shown in FIG. 6 to the state shown in FIG. When the force acting in the direction that hinders the expansion and contraction of the one actuator decreases due to the own weight of the truss structure by extending and contracting the other actuator prior to the one actuator, The expansion / contraction driving order of each actuator is determined so that the expansion / contraction of the actuators precedes the expansion / contraction of the one actuator.

Hereinafter, the driving states of the actuators A1 to A5 will be described in detail. 3 (B) to 4 (E)
Shows the progress at that time. When the first actuator A1 to the fourth actuator A4 are sequentially contracted, the truss structure standing upright so as to fall down to the left side in the figure gradually rises at the tip thereof and stands up. Second to fifth actuators A2
When all of .about.A5 are contracted, as shown in FIG. 4 (E), they are slightly inclined rightward in the figure. In this state,
A moment is applied to the first actuator A1 closest to the support end by an amount corresponding to the tip of the truss structure 2 slightly tilting rightward in the figure. Therefore, the second to fifth actuators A
The second to fifth actuators A2 to A5 are slightly extended to slightly reduce the amount of contraction of the second to fifth actuators A2 to A5, and the moment acting on the fifth actuator A5 is reduced accordingly. 5 Start contraction of the actuator. On the way, as shown in FIG. 4 (G), the entire deformable truss structure 2 comes to be in a state of standing upright on the ground, and
When the actuator A5 is expanded and contracted toward the target expansion and contraction amount, the deformable truss structure 2 becomes a state as shown in FIG. 5 (H), and finally a state as shown in FIG. 5 (I). become.

After the contraction of the first actuator A1 is completed, as shown in FIGS. 5J to 6L, the remaining actuators A2 to A5 are contracted in the order closer to the support end. Then, the actuator A farthest from the support end
When the member 5 contracts, the deformation of the deformable truss structure 2 is completed as shown in FIG.

In this way, by determining the expansion / contraction drive order of each actuator so as to reduce the force acting in the direction that hinders the expansion / contraction of the actuator, each actuator can be extended / contracted with the minimum necessary driving force. It is possible to reduce the size of the device and to avoid an increase in the size, weight, and cost of the entire structure.

=== Other Embodiments === (1) In the method of controlling the shape of the variable shape truss structure according to the present invention, in addition to the variable shape truss structure described in the above embodiment, It may be applied to other types of deformable truss structures.

(2) In the above embodiment, the case where all the actuators included in the deformable truss structure expand and contract has been described. However, the present invention is not limited to such a case, and a plurality of actuators may be used. It is also applied when a part is stretched.

[0023]

According to the method of controlling the shape of the variable-shaped truss structure according to the present invention, the other actuator is expanded and contracted prior to one actuator, so that the other actuator can be moved in accordance with the weight of the truss structure. When the force acting in the direction that hinders expansion and contraction decreases, each actuator expands and contracts in the order that the expansion and contraction of other actuators precedes the expansion and contraction of one actuator. Therefore, the size of each actuator can be reduced, and the size, weight, and cost of the entire structure can be avoided.

[Brief description of the drawings]

FIGS. 1A to 1E are views showing an embodiment when a shape control method for a variable-shaped truss structure according to the present invention is applied to a cantilever variable-shaped truss frame.

FIG. 2 is a diagram showing another variable shape truss structure to which the shape control method according to the present invention is applied.

FIGS. 3 (B) to 3 (D) are diagrams illustrating a deformation procedure when the shape control method according to the present invention is applied to the variable shape truss structure shown in FIG.

FIGS. 4 (E) to 4 (G) are diagrams for explaining a deformation procedure when the shape control method according to the present invention is applied to the variable shape truss structure shown in FIG. 2, following FIG.

5 (H) to (J) are diagrams illustrating a deformation procedure when the shape control method according to the present invention is applied to the variable shape truss structure shown in FIG. 2, following FIG.

FIGS. 6 (K) to 6 (M) are diagrams illustrating a deformation procedure when the shape control method according to the present invention is applied to the variable shape truss structure shown in FIG. 2, following FIG.

FIGS. 7A and 7B are diagrams showing a procedure for deforming an example of a generally well-known variable shape truss structure.

[Description of Signs] 2,20 Variable-shaped truss structure 4 Basic constituent elements 6 String material 8 Bundle material 10 Diagonal material 12 Hinge pin 22 Fixed truss 24 Variable truss 26 Pin hinge 28 Sap material 34 Variable member

Claims (2)

[Claims] 1. A method of controlling a variable-shaped truss structure having a plurality of telescoping truss members formed of telescopic actuators, the shape of which is changed by the expansion and contraction of each actuator, to a target shape. By calculating the target amount of expansion and contraction of each actuator for realizing the above, by expanding and contracting another actuator prior to one actuator, in a direction in which expansion and contraction of the one actuator is hindered by the weight of the truss structure. When the acting force decreases, the expansion and contraction drive order of each actuator is determined so that the expansion and contraction of the other actuator precedes the expansion and contraction of the one actuator, and each actuator is moved to the respective target expansion and contraction according to the expansion and contraction drive order. A method for controlling the shape of a deformable truss structure, characterized in that the truss structure is expanded or contracted toward an amount. 2. A method for controlling the shape of a variable-shaped truss structure having one end fixed, comprising a plurality of telescoping truss members constituted by telescopic actuators, and changing the shape by expansion and contraction of each actuator. Prior to one actuator, by expanding and contracting another actuator located on the tip side of the truss structure relative to the one actuator, the expansion and contraction of the one actuator is caused by the weight of the truss structure. A shape control method for a deformable truss structure, characterized in that when the force acting in the obstructing direction decreases, the other actuator is expanded and contracted prior to the one actuator.