Flexible self-actuated structure and associated method

Details Flexible self-actuated structure and associated method Flexible self-actuated structure and associated method

2000-03-27

2001-07-24

Wong, Don (Department: 2821)

Communications: radio wave antennas

Antennas

Antenna components

C343S881000, C343SDIG002

Reexamination Certificate

active

06266030

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates in general to a flexible self-actuated structure, and more particularly to a self-actuated structure useful in supporting land and space based communications.
BACKGROUND OF THE INVENTION
Structures that can be collapsed during transit and deployed upon reaching their destination have been widely used, particularly in situations in which cargo space is limited or otherwise at a premium. Advantageously, collapsible structures may be stowed compactly in a vehicle while not in use, and then deployed to a desired configuration to perform a given application. Although the space-saving characteristics of collapsible structures benefit many applications, space applications in particular stand to benefit to a high degree due to the limited amount of cargo space onboard a spacecraft and the high cost of space travel.
Large antennas are oftentimes deployed to orbit the earth and to perform various tasks, such as collecting radar images, tracking ground-based and air-based targets, and providing high-bandwidth communications. Such antennas usually require relatively large apertures, as well as heavy electronics packaging and support structures. In addition, most antennas cannot be retracted and collapsed once fully deployed. As a result, the antennas cannot be collapsed into a spacecraft and returned to Earth for future applications. Although lightweight electronics packaging and support structures may reduce total mass, the antennas still generally require large apertures such that the overall antenna structure remains quite large. Since the antennas are generally transported into space onboard a spacecraft, an important design factor is the ability to efficiently package a large antenna structure inside of the launch vehicle payload volume, while still permitting the antenna to be deployed once in space.
Several approaches currently are used to address the transportation of large deployable antenna systems on a spacecraft. One method utilizes discrete folding panels that are capable of folding into a relatively small size, but that deploy into the larger antenna structure when in orbit. Under this approach, however, the folded panels produce a dense stowed package that leaves little room for storing other objects. Another method commonly used to stow large deployable space structures that are formed of a number of tubes is to fold and/or nest the tubes. The tubes can then be unnested and unfolded to produce a truss structure of a desired size, shape, and stiffness. Under this approach, however, the size of the deployed structure and the complexity of the electronics packaging being supported by the structure requires a highly complex system of hinges, cables, and drive components. As a result, the structure is generally relatively unreliable and is disadvantageously heavy.
It would therefore be desirable to provide a deployable antenna structure that not only is relatively light, but can also be stowed and deployed in an effective manner. In order to facilitate the deployment of the antenna, particularly in space applications, it would be desirable to provide a means for deploying and/or retracting the structure without the use of drive components or other motors. Finally, it would be desirable to provide an antenna structure that could be retracted into a vehicle to be used again for future applications.
Accordingly, while a variety of collapsible structures, including antennas, have been developed, most of the structures remain disadvantageously heavy and oftentimes consume a substantial portion of the cargo space. In addition, a number of the collapsible structures require a complex system of hinges, cables and drive components for their deployment. Thus, a collapsible structure, such as an antenna, that can be stowed in a compact manner, can be self-deployed and need not include a mechanically complex deployment system is desirable, particularly for space applications.
SUMMARY OF THE INVENTION
These and other needs are provided, according to the present invention, by a self-actuated structure, such as an antenna structure, that can be stowed in a compact manner and can be deployed in a self-actuated fashion without requiring a complex system of hinges, drive components and the like. As such, the self-actuated structure is particularly well suited for space applications, such as antennas including phased array antennas. It should be noted, however, that the self-actuated structure is not limited to antenna structures as described herein, but may include any rolling or folding structure that requires minimal stowage volume and high reliability deployment.
According to the present invention, the self-actuated antenna structure includes a flexible skin, preferably comprised of a composite material, and an array of electronics packages attached to the skin. In the stowed position, the flexible skin is deformed or folded to a compact shape so as to minimize the portion of the vehicle payload volume that is consumed by the stowed structure. The flexible skin can also store potential energy when in the stowed position. Once stowed, the structure of the present invention preferably defines an internal payload volume in which additional payload, such as additional antenna structures, may be stored for deployment at a later time. The antenna structure includes at least one ring connected to the flexible skin that provides a controlled shape to the stowed structure, thus allowing for control of the internal payload volume. In this regard, the rings may have many different shapes, such as a polygon or circle, depending on the vehicle payload volume. In one advantageous embodiment, the rings are circular such that the stowed shape is substantially cylindrical. Regardless of their shape, the rings act to provide structural stability in both the stowed and deployed positions. In addition, the rings may be hinged to enable the rings to partially open and close for deploying any additional payload.
Advantageously, the structure also includes a plurality of self-deploying stiffeners, which may be attached to the flexible skin by a fastener, epoxy, or the like. The stiffeners are designed to store potential energy such that the stiffeners can move the self-actuated structure from a first position, such as a stowed position, to a second position, such as a deployed position, without the application of external forces. In this regard, the stiffeners can have an unbiased relaxed shape in the absence of external forces and a biased or buckled shape, such as a flat shape, upon the application of external bias forces. As such, the application of external bias forces can cause the stiffeners to assume the biased shape which moves the structure into the first position, typically a stowed position, while the removal of external bias forces allows the stiffeners to assume the unbiased relaxed shape which moves the structure into the second position, typically a deployed position.
The structure can also include a plurality of cables and a motor that cooperate to apply the external forces that move the structure from the deployed position to the stowed position, such as by pulling the flexible skin toward and around the rings. The external forces cause the self-deploying stiffeners to buckle or collapse, thereby storing potential energy in the self-deploying stiffeners. This energy is later used to deploy the structure from the stowed position to the deployed position without having to apply any additional external force. During the deployment, the cables can control the deployment rate. In an alternative embodiment, the stiffeners may be in an unbiased or relaxed shape while the structure is in the stowed position, wherein the cables must apply external forces to pull the skin away from the rings and toward the deployed or biased position, resulting in potential energy being stored in the stiffeners while in the deployed position. The stored energy is later used to stow the structure from the deployed position, while the cables control the stowage rate. In bot

Affiliated with

Also associated with

Rating

Flexible self-actuated structure and associated method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Flexible self-actuated structure and associated method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flexible self-actuated structure and associated method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2532036