Embodiments of the disclosure generally relate to antenna structures. In particular, embodiments of the disclosure relate to deployable antenna structures and associated components and methods.
Reflectors for concentrating radiofrequency (RF) radiation are employed in a variety of antennas installed in spacecraft or mounted on the ground. Reflectors for concentrating solar radiation are employed as solar energy collectors in systems for converting solar energy into electrical energy.
Satellite and communications technologies often require that space-based devices and other high technology machinery be lightweight yet durable to withstand the effects of the space environment. Such devices, however, must also be practically devised to be launched from Earth in a small package and deployed in space autonomously. For example, a vehicle intended to be launched into space may have cross-sectional limitations and weight limitations to accommodate the launch vehicle, such as a rocket. The effectiveness of an antenna may be associated with a surface area of the antenna. For example, increasing a surface area of an antenna may increase the quality and/or coverage of signals received by and/or transmitted by the antenna. An expandable antenna may be stored in a small space during transportation and may expand to form an antenna with a larger surface area when deployed.
Embodiments of the disclosure include a deployable reflector structure. The deployable reflector structure includes a base in a central portion of the deployable reflector structure. The antenna structure further includes one or more arms configured to extend from the base. The antenna structure also includes an expandable structure coupled to the one or more arms. The antenna structure further includes a reflector mesh coupled between the one or more arms and the base.
Another embodiment of the disclosure includes an expandable antenna structure. The expandable antenna structure at least two arms. The expandable antenna structure further includes an expandable structure coupled to the at least two arms. The expandable antenna structure also includes a first carrier slidably coupled to a first arm of the at least two arms. The first carrier is coupled to a section of the expandable structure on a first end of the section of the expandable structure. The expandable antenna structure further includes a second carrier slidably coupled to a second arm of the at least two arms. The second carrier is coupled to a second end of the section of the expandable structure opposite the first end. The expandable antenna structure also includes a cable drive apparatus. The expandable antenna structure further includes a driving cable coupled to the cable drive apparatus, the driving cable passing through diagonal truss structures in the section of the expandable structure. The diagonal truss structures define an alternating diagonal path through the section of the expandable structure from the first end of the section of the expandable structure to the second end of the expandable structure.
Another embodiment of the disclosure includes a method of extending an antenna. The method includes rotating an arm away from a tower. The method further includes spooling a drive cable onto a spool. The method also includes pulling a carrier along the arm with the drive cable. The method further includes shortening a diagonal truss member of an extendable structure with the drive cable causing the extendable structure to expand away from the tower.
While the specification concludes with claims particularly pointing out and distinctly claiming embodiments of the disclosure, the advantages of embodiments of the disclosure may be more readily ascertained from the following description of embodiments of the disclosure when read in conjunction with the accompanying drawings in which:
The following description provides specific details, such as material compositions, shapes, and sizes, in order to provide a thorough description of embodiments of the disclosure. However, a person of ordinary skill in the art would understand that the embodiments of the disclosure may be practiced without employing these specific details. Indeed, the embodiments of the disclosure may be practiced in conjunction with conventional techniques employed in the industry.
Drawings presented herein are for illustrative purposes only, and are not meant to be actual views of any particular material, component, structure, device, or system. Variations from the shapes depicted in the drawings as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein are not to be construed as being limited to the particular shapes or regions as illustrated, but include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as box-shaped may have rough and/or nonlinear features, and a region illustrated or described as round may include some rough and/or linear features. Moreover, sharp angles that are illustrated may be rounded, and vice versa. Thus, the regions illustrated in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shape of a region and do not limit the scope of the present claims. The drawings are not necessarily to scale. Additionally, elements common between figures may retain the same numerical designation.
As used herein, the terms “configured” and “configuration” refers to a size, a shape, a material composition, a material distribution, orientation, and arrangement of at least one feature (e.g., one or more of at least one structure, at least one material, at least one region, at least one device) facilitating use of the at least one feature in a pre-determined way.
As used herein, the term “substantially” in reference to a given parameter means and includes to a degree that one skilled in the art would understand that the given parameter, property, or condition is met with a small degree of variance, such as within acceptable manufacturing tolerances. By way of example, depending on the particular parameter, property, or condition that is substantially met, the parameter, property, or condition may be at least 90.0 percent met, at least 95.0 percent met, at least 99.0 percent met, at least 99.9 percent met, or even 100.0 percent met.
As used herein, “about” or “approximately” in reference to a numerical value for a particular parameter is inclusive of the numerical value and a degree of variance from the numerical value that one of ordinary skill in the art would understand is within acceptable tolerances for the particular parameter. For example, “about” or “approximately” in reference to a numerical value may include additional numerical values within a range of from 90.0 percent to 110.0 percent of the numerical value, such as within a range of from 95.0 percent to 105.0 percent of the numerical value, within a range of from 97.5 percent to 102.5 percent of the numerical value, within a range of from 99.0 percent to 101.0 percent of the numerical value, within a range of from 99.5 percent to 100.5 percent of the numerical value, or within a range of from 99.9 percent to 100.1 percent of the numerical value.
As used herein, relational terms, such as “beneath,” “below,” “lower,” “bottom,” “above,” “upper,” “top,” “front,” “rear,” “left,” “right,” and the like, may be used for ease of description to describe one element's or feature's relationship to another element(s) or feature(s) as illustrated in the drawings. Unless otherwise specified, the spatially relative terms are intended to encompass different orientations of the materials in addition to the orientation depicted in the figures. For example, if materials in the figures are inverted, elements described as “below” or “beneath” or “under” or “on bottom of” other elements or features would then be oriented “above” or “on top of” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below, depending on the context in which the term is used, which will be evident to one of ordinary skill in the art. The materials may be otherwise oriented (e.g., rotated 90 degrees, inverted, flipped) and the spatially relative descriptors used herein interpreted accordingly.
As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
As used herein, the term “and/or” means and includes any and all combinations of one or more of the associated listed items.
As used herein, the terms “vertical,” “longitudinal,” “horizontal,” and “lateral” are in reference to a major plane of a structure and are not necessarily defined by earth's gravitational field. A “horizontal” or “lateral” direction is a direction that is substantially parallel to the major plane of the structure, while a “vertical” or “longitudinal” direction is a direction that is substantially perpendicular to the major plane of the structure. The major plane of the structure is defined by a surface of the structure having a relatively large area compared to other surfaces of the structure. With reference to the drawings, a “horizontal” or “lateral” direction may be perpendicular to an indicated “Z” axis, and may be parallel to an indicated “X” axis and/or parallel to an indicated “Y” axis; and a “vertical” or “longitudinal” direction may be parallel to an indicated “Z” axis, may be perpendicular to an indicated “X” axis, and may be perpendicular to an indicated “Y” axis.
As described above, antennas may be expandable, such that the antenna may be stored in a small space during transportation and may expand to form an antenna with a larger surface area when deployed. Expandable antennas may be formed from a conductive mesh, such as a knitted gold-plated molybdenum wire. The mesh antennas may be coupled to an expandable structure. A conventional expandable structure includes a drive configured to expand the structure coupled to a point on a perimeter of the expandable structure. Positioning the drive on the perimeter of the structure may limit a size of the expandable structure. The drive positioned on the perimeter of the structure may also limit mounting locations for the expandable antenna. Furthermore, expandable structures with no central support may have reduced surface accuracy and stiffness.
In the stowed configuration, the arms 106 may be positioned in a substantially parallel arrangement with the tower 104 and the expandable structure 108 may extend about the circumference of the tower 104, substantially surrounding the tower 104. The antenna 100 may form a substantially cylindrical shape defined by the arms 106 and the expandable structure 108. The cylindrical shape of the stowed antenna 100 may have a major dimension (e.g., width, diameter, radius, apothem, etc.) of less than or equal to the corresponding major dimension of the base 110. For example, if the base 110 is circular, the cylindrical shape formed by the arms 106 and the expandable structure 108 may have a diameter less than or equal to a diameter of the base 110. In some embodiments, the base 110 may have a non-circular shape, such as a square shape, a triangular shape, an oval shape, etc.
The arms 106 may include a shaft 112 and a tip 114. The shaft 112 may have a substantially constant cross-sectional area. For example, the shaft 112 may be rectangular as illustrated in
Rotating the arms 106 away from the tower 104 may cause the expandable structure 108 to begin expanding radially away from the tower 104. For example, portions of the expandable structure 108 may be coupled to the arms 106 at movable connection points 204. The movable connection points 204 may cause the expandable structure 108 to extend to maintain the connection between the expandable structure 108, the movable connection points 204, and the arms 106.
The movable connection points 204 may move along the arms 106 in an outward radial direction away from the tower 104, which may further expand the expandable structure 108, as illustrated in
When the expandable structure 108 is at its largest diameter, a reflector 402, such as a mesh reflector, may be stretched across the expandable structure 108, as illustrated in
In some embodiments, the antenna 100 may include two mesh 502, 504, as illustrated in
The meshes 502, 504 may be formed from a flexible mesh, such as a knitted or woven material formed from chords or wires of a reflective material, such as gold-plated molybdenum wire. Some of the chords or wires may extend to joints 508, 512 of the expandable structure 108 and may act as securing chords 506, 510. In other examples, additional chords or wires may be coupled to the mesh reflectors 502, 504 to act as securing chords 506, 510.
The securing chords 506, 510 may couple the associated reflector 502, 504 to the expandable structure 108. In some embodiments, the securing chords 506, 510 may be coupled directly to the expandable structure 108, such that as the expandable structure 108 expands to its extended size, the reflectors 502, 504 may extend with the expandable structure 108. In other embodiments, the securing chords 506, 510 may be coupled to a driving cable configured to extend the reflectors 502, 504 after the expandable structure 108 has extended to its extended size.
In some examples, the hinged caps 608 and/or the end caps 602 may also be coupled to the respective arms 106 through a hardware connection (e.g., bolts, screws, rivets, etc.). In other examples, the hinged caps 608 and/or the end caps 602 may be secured to the arms 106, through a permanent connection, such as a weld, solder, adhesive, bonding, etc. In another example, the hinged caps 608 and/or the end cap 602 may be formed as part of the arm 106.
The arms 106 may be formed from a rigid light weight material, such as light weight metal materials (e.g., aluminum, titanium, etc.), polymer materials (e.g., polyetheretherketone (PEEK), poly(methyl methacrylate) (PMMA), etc.), or composite materials (e.g., carbon fiber, fiberglass, etc.). In some embodiments, the hinged caps 608 and the end caps 602 may be formed from the same material as the arms 106. In other embodiments, the hinged caps 608 and/or the end caps 602 may be formed from a different rigid light weight material than the arms 106 and attached thereto.
The arms 106 may be substantially hollow components, such as tubular structures (e.g., rectangular tubes, cylindrical tubes, etc.). The tubular structures of the arms 106 may facilitate components, such as driving cables, passing through the arms 106. For example, cables may be run internally through the hollow portions of the arms 106. In some embodiments, cables may also be run externally along the arms 106. The cables may be configured to apply forces to different elements of the antenna 100 to expand the different components of the antenna 100. The tubular structures of the arms 106 may also result in a reduction in weight of the arms 106. In aerospace applications, weight considerations may substantially drive designs, such that a reduction in weight may facilitate increases in size and/or the inclusion of additional components in the associated vehicle. In some embodiments, the arms 106 may be configured to increase in length when they expand, such as through a telescoping feature. For example, the arms 106 may include one or more nested tubes that may telescope out to increase a length of the arms 106 in an extended (e.g., a deployed) position.
The arms 106 may also include anchors 606 configured to secure rails 604 run externally along the arms 106. The rail 604 may be configured to receive a rolling connector (e.g., a trolley, roller, movable connection point 204, movable connector, etc.) and secure the rolling connector to the associated arm 106. The rail 604 and the interface with the rolling connector is described in further detail below with respect to
The end cap 602 may have a major dimension (e.g., width, diameter, radius, etc.) that is less than a same major dimension of the hollow portion of the arm 106. The end cap 602 may be disposed into the hollow portion of the arm 106. A gap 704 may be defined between the arm 106 and the end cap 602 as illustrated in
The hinge pulley 806 may be secured to a base hinge 802, which is secured to the base 110. The base hinge 802 may be the portion of the hinged connection 202 that remains stationary throughout the expansion process. The hinge pulley 806 may be offset from a pivot 804 between the base hinge 802 and the hinge cap 608. In some embodiments, the hinge pulley 806 is configured to route the hinge cable 812 into an interior portion of the arm 106. The pivot 804 may form the hinged connection 202 between the base hinge 802 and the hinge cap 608, such that the hinge cap 608 and the respective arm 106 may rotate about the pivot 804 when moving from the stowed position illustrated in
In some embodiments, the hinge pulley 806 may include multiple pulleys. For example, the hinge pulley 806 may include multiple pulleys arranges in series with a single hinge cable 812 passing through each of the multiple pulleys and configured to act as a force multiplier. In a series arrangement, the hinge pulleys 806 may include hinge pulleys 806 attached to the base hinge 802 and hinge pulleys 806 attached to the hinge cap 608, such that the hinge cable 812 passing between the hinge pulleys 806 attached to each of the base hinge 802 and the hinge cap 608 may multiply the tensile force in the hinge cable 812 to pull the hinge cap 608 toward the base hinge 802. In another example, the hinge pulley 806 may include multiple pulleys arranged in parallel with multiple hinge cables 812 configured to divide the tensile force across the multiple hinge cables 812.
Tension may be applied to the hinge cable 812 through another component, such as a spool, which may be housed in a drive housing 810. In some embodiments, the distance between the pivot 804 and the hinge pulley 806 may generate a moment (e.g., torque) about the pivot 804 through the applied tension in the hinge cable 812. The moment about the pivot 804 generated by the tension in the hinge cable 812 may cause the arm 106 to rotate about the pivot 804. As the arm 106 rotates about the pivot 804, a length of the hinge cable 812 between the anchor 808 and the hinge pulley 706 may be reduced. The component in the drive housing 810 may continue to apply tension to the hinge cable 812, such as by drawing in excess hinge cable 812 (e.g., onto a spool) accommodating the reduction in length of the hinge cable 812. In other embodiments, the pivot 804 may be driven separately from the hinge cable 812. For example, the pivot 804 may be driven by an actuator and the hinge cable 812 may pass through the arm 106 to drive a separate component, such as a trolley, carrier, roller, etc., as described in further detail below.
The drive housing 810 may include a housing pulley 814 coupled to a bracket 820 (the bracket 820 is not shown in
In some embodiments, the hinge cap 608 and the base hinge 802 may include latching components that may engage to latch hinge cap 608 to the base hinge 802 when the arm 106 reaches the fully extended position as illustrated in
The carrier 1002 may be coupled to the rails 604 though wheels 1006. The wheels 1006 may have a shape substantially complementary to the rails 604 as described in further detail below with respect to
The expandable structure 108 may be coupled to the carrier 1002 through a pivot 1004, such that the expandable structure 108 may remain in substantially a same orientation relative to the tower 104 (
The carrier 1002 may include multiple cables 1010 coupled to the carrier 1002. The cables 1010 may be configured to move (e.g., pull) the carrier 1002 to the distal end of arm 106. The cables 1010 may also be configured to expand the expandable structure 108. As described above, some of the cables 1010 may also be configured to cause the arm 106 to rotate about the hinged connection 202 (
The arm 106 may include a stop 1102 coupled to the end cap 602. The carrier 1002 may be configured to rest against the stop 1102 when the carrier 1002 is in the fully extended position. The one or more of the cables 1010 (e.g., a drive cable) may be configured to pull the carrier 1002 against the stop 1102. In some embodiments, the one or more cables 1010 may apply an additional force (e.g., a pre-load force) pulling the carrier 1002 against the stop 1102, which may substantially prevent the carrier 1002 from moving down the arm 106 away from the stop 1102. In some embodiments, the one or more cables 1010 may pass through a load washer 1112 coupled between the pulley 1106 and/or the cable termination 1110 coupled to the end cap 602. The load washer 1112 may provide additional tensile forces to the one or more cables 1010. The stop 1102 may be coupled to the end cap 602 with hardware 1116, such as screws, bolts, studs, pins, etc. The hardware 1116 may pass through a slot 1118 in the stop 1102. The slot 1118 may facilitate adjustments to the position of the carrier 1002. For example, the hardware 1116 may be loosened and a position of the stop 1102 may be adjusted. The hardware 1116 may then be tightened to clamp the stop 1102 to the end cap 602.
The carrier 1002 may also include a latch 1108 configured to retain the carrier 1002 in the fully extended position. The latch 1108 may be configured to engage once the carrier 1002 has reached the fully extended position and substantially prevent the carrier 1002 from traveling down the arm 106 in a direction away from the distal end of the arm 106. As illustrated in
In some embodiments, the stationary component 1204 may have a wedge shape. For example, a top surface 1208 of the stationary component 1204 may form an inclined plane relative to the arm 106. The top surface 1208 may include multiple ridges or teeth, which may be configured to act as a ratcheting interface, such that once the movable component 1202 passes over the top surface 1208 the movable component 1202 may be substantially prevented from reversing direction. The movable component 1202 may extend from the carrier 1002 at a downward angle away from the direction of travel. The angle of the movable component 1202 may facilitate the movable component 1202 moving away from the arm 106 under the influence of the top surface 1208 of the stationary component 1204 when the carrier 1002 moves toward the distal end of the arm 106 while catching against the side surface 1206 and/or the ridges or teeth in the top surface 1208 when the carrier 1002 attempts to move in an opposite direction away from the distal end of the arm 106.
Each wheel 1006 may be coupled to the carrier 1002 through one or more bearings 1302. The bearings 1302 may facilitate substantially free rotation of the wheels 1006 relative to the carrier 1002. The wheels 1006 may also include a retaining element 1304 extending from a shaft 1312 of the wheel 1006. The retaining element 1304 may extend to a greater radius than the passage defined by the bearings 1302 through which the shaft 1312 of the wheel 1006 passes. The retaining element 1304 may be configured to substantially prevent the shaft 1312 from being removed through the bearings 1302. In some embodiments, the shaft 1312 may be a pin extending through the shaft 1312. In other embodiments, the retaining element 1304 may be an element configured to extend from the shaft 1312 in more than two directions, such as a disk, cone, or other element.
As described above, the expandable structure 108 may be a truss-like structure including multiple segments 302 formed from two sets of parallel structures, such as rods, pins, shafts, etc. The two sets of parallel structures may include parallel truss members 304, 306 (e.g., a bottom truss member 304 and a top truss member 306) and parallel vertical truss members 308. Each of the vertical truss members 308 may have substantially the same length and each of the bottom truss members 304 may have substantially the same length as the corresponding top truss members 306. Thus, each segment 302 may form a parallelogram. Each segment 302 may also include a diagonal truss structure 310 extending diagonally between two corners of the segment 302, such as between a corner between the top truss member 306 and the vertical truss member 308 and a corner between the bottom truss member 304 and an adjacent vertical truss member 308. The diagonal truss structure 310 may be configured to change in length such that a shape of the segment 302 may change during deployment until each of the corners form angles of about 90°. When each of the corners form angles of about 90°, the expandable structure 108 may be at its largest diameter as illustrated in
The structures of the expandable structure 108 may be joined at each vertical truss member 308 by a valley node 1402 or a ridge node 1404. The valley node 1402 may be configured to receive three elements, such as two truss members 304, 306 (e.g., two top truss members 306 or two bottom truss members 304) and a vertical truss member 308. The ridge node 1404 may be configured to receive five elements, such as two truss members 304, 306 (e.g., two top truss members 306 or two bottom truss members 304), two diagonal truss structures 310, and a vertical truss member 308. Each vertical truss member 308 may have a valley node 1402 on a first end of the vertical truss member 308 and a ridge node 1404 on a second end of the vertical truss member 308 opposite the first end. Similarly, each bottom truss member 304 and each top truss member 306 may extend between a valley node 1402 and a ridge node 1404. The valley nodes 1402 and ridge nodes 1404 may alternate sides (e.g., top side and bottom side) of the expandable structure 108 at each vertical truss member 308. The alternating position of the valley nodes 1402 and the ridge nodes 1404 may facilitate the diagonal truss structures 310 alternating between top and bottom of the expandable structure 108 at each vertical truss member 308.
As described above, the expandable structure 108 may be coupled to the carriers 1002 on each arm 106. Each carrier 1002 may be coupled to the expandable structure 108 through one of the ridge nodes 1404. This may facilitate cables passing from the carriers 1002 into the diagonal truss structures 310 as described in further detail below. The carriers 1002 may move (e.g., pull) the associated ridge nodes 1404 to the distal end of the associated arms 106. The distal end of the associated arms 106 may define an outer circumference of the expandable structure 108. For example, the distal end of each arm 106 may be a distance from the center of the antenna 100 that is substantially equal to the radius of the expandable structure 108 in its fully extended form.
The valley nodes 1402 and the ridge nodes 1404 may include fittings 1504, 1506, 1508, which may be configured to rotate relative to the valley nodes 1402 and the ridge nodes 1404, to facilitate the expansion of the expandable structure 108. For example, the valley nodes 1402 and the ridge nodes 1404 may be fixed relative to the associated vertical truss member 308. The fittings 1504, 1506, 1508 may facilitate the rotation of the associated truss members 304, 306 and diagonal truss structures 310 relative to the vertical truss members 308. In a fully retracted position the truss members 304, 306 and the diagonal truss structures 310 may be substantially parallel to the vertical truss members 308. As the carriers 1002 travel along the respective arms 106, an angle 1502 between the truss members 304, 306 and the vertical truss member 308 may be reduced as the expandable structure 108 approaches the expanded position. For example, in the fully retracted position, the angle 1502 may be about 180°, such as greater than about 1600 or greater than about 170°. In a fully expanded position, the angle 1502 may be about 90°, such as between about 800 and about 100°, or between about 850 and about 95°.
The valley nodes 1402 may include two fittings 1504, which may be configured to couple to the adjacent truss members 304, 306. For example, if the valley node 1402 is positioned on a bottom side of the associated vertical truss member 308, the fittings 1504 may be coupled to the two adjacent bottom truss members 304, as illustrated in
As described above, the diagonal truss structures 310 may be configured to change length to change the angle 1502 between the truss members 304, 306 and the vertical truss member 308. For example, the diagonal 310 may be a telescoping element, such as several nested tubes configured to expand or retract. In the embodiment illustrated in
In some cases, the expandable structure 108 may be operably divided into sections 1614. For example, the sections 1614 may be separated at each arm 106, such that each section 1614 extends between two adjacent arms 106. Each section 1614 may have a cable 1612 passing through each of the diagonal truss structures 310 in the section 1614. The cable 1612 may be terminated on a first end of the section 1614 and may be coupled to a spool 1602 on a second end opposite the first end. Thus, as the cable 1612 is wound onto the spool 1602, such as by a motor 1604 turning the spool 1602, each of the diagonal truss structures 310 in the section 1614 may shorten by substantially a same amount. The cable 1612 may pass through pulleys 1610 at each of the ridge nodes 1404, which may reduce friction where the direction of the cable 1612 changes direction, which may facilitate a balanced tensile force through the cable 1612 throughout the section 1614.
In some cases, the section 1614 may be operably coupled to an adjacent section 1614, such as through a synchronizing mechanism 1608, which may synchronize the two sections 1614. Synchronizing the two sections 1614 may facilitate opening each section 1614 of the expandable structure 108 at substantially a same rate, such that the expandable structure 108 expands in a substantially uniform manner. In some embodiments, the synchronizing mechanism 1608 may be a synchronizing cable. In other embodiments, the synchronizing mechanism 1608 may be a mechanical connection, such as interlocking gears or teeth. For example, the fittings 1504 on the valley node 1402 coupling to sections 1614 together may include a geared interface, such that the two fittings 1504 rotate at substantially the same rate.
In some embodiments, the expandable structure 108 may include one or more sensors 1606, such as end switches, position sensors (e.g., potentiometers, displacement sensors, Hall Effect sensor, etc.), pressure sensors, strain sensors, etc. The sensors 1606 may provide information to a controller, which may make decisions and/or change control commands based on readings from the one or more sensors 1606.
As illustrated in
The drive cables 1708a, 1708b, 1708c may be directed to different portions of the spool 1702 through cable nozzles 1706a, 1706b, 1706c. For example, a first cable nozzle 1706a may direct a first drive cable 1708a to a bottom portion of the spool 1702, a second cable nozzle 1706b may direct a second drive cable 1708b to a center portion of the spool 1702, and a third cable nozzle 1706c may direct a third drive cable 1708c to a top portion of the spool 1702. This may facilitate the multiple drive cables 1708a, 1708b, 1708c being wound onto the spool 1702 without interfering with adjacent drive cables 1708a, 1708b, 1708c. The cable nozzles 1706a, 1706b, 1706c may be secured to a nozzle carrier 1714, which may maintain a uniform spacing between the cable nozzles 1706a, 1706b, 1706c. The nozzle carrier 1714 may be configured to move relative to the spool 1702 in an axial direction. For example, the nozzle carrier 1714 may be configured to substantially prevent the drive cables 1708a, 1708b, 1708c from overlapping on the spool 1702 by moving axially up or down the spool 1702 as the spool 1702 rotates, such that the drive cables 1708a, 1708b, 1708c are spooled in a helical manner up or down the spool 1702.
The spool 1702 may include a guide roller 1712 configured to maintain the drive cables 1708a, 1708b, 1708c in contact with the surface of the spool 1702. The guide roller 1712 may further assist the cable nozzles 1706a, 1706b, 1706c in guiding the drive cables 1708a, 1708b, 1708c onto the spool 1702 by restricting the drive cables 1708a, 1708b, 1708c from overlapping one another.
The drive cables 1708a, 1708b, 1708c may be guided into the cable nozzles 1706a, 1706b, 1706c through one or more pulleys 1710a, 1710b. For example,
The drive 1700 may also receive synchronizing cables 1802. The synchronizing cables 1802 may run between the different sections (e.g., sections 1614 (
The drive cable 1708a may pass through a drive pulley 2004, which may direct the drive cable 1708a up the arm 106 to the carrier 1002 (
The synchronizing cable 1802 may pass through multiple synchronizing pulleys 2002, 2006. The synchronizing pulleys 2002, 2006 may include arm synchronizing pulleys 2002 and base synchronizing pulleys 2006. The synchronizing cable 1802 may pass through a base synchronizing pulley 2006 to an arm synchronizing pulley 2002 down the arm 106 to the carrier 1002 (
The cable arrangement illustrated in
Another spool 1702 may be coupled to a carrier drive cable 2104, which may pass through a pulley 2108 at a distal end of the arm 106 and then be coupled to a carrier 1002. As the spool 1702 winds the carrier drive cable 2104 onto the spool the carrier drive cable 2104 pulls the carrier 1002 toward the pulley 2108 at the distal end of the arm 106. Each of the carrier drive cables 2104 may be coupled to the same spool 1702 similar to the hinge cables 812 described above, such that one spool 1702 may drive all of the carriers 1002.
A third spool 1702 may be coupled to an expandable structure drive cable 2102. The expandable structure drive cable 2102 may enter a section (e.g., sections 1614 (
The second spool 1702 may be coupled to a drive cable 2202. The drive cable 2202 may extend down a first arm 106 where the drive cable 2202 may enter a first side of a section (e.g., section 1614 (
The arrangement illustrated in
The second spool 1702 may be coupled to a drive cable 2304. The drive cable 2304 may extend down a first arm 106 where the drive cable 2202 may enter a first side of a section (e.g., section 1614 (
The arrangement illustrated in
The second spool 1702 may be coupled to a drive cable 2402. The drive cable 2402 may extend down a first arm 106 where the drive cable 2202 may pass around a pulley 2404 at a distal end of the first arm 106. The drive cable 2402 may then enter a first side of a section (e.g., section 1614 (
The arrangement illustrated in
Embodiments of the disclosure may facilitate the creation of expandable antenna structures that expand from a central hub. The expandable antenna structures according to embodiments of the disclosure may have greater rigidity when deployed than expandable antenna structures that expand from a side mounted structure. The increased rigidity may facilitate, for example, rapid slewing of the associated antenna system independent of the main body of an associated satellite to track objects from space The mass of the expandable antenna structures may also be less than the mass of side mounted expandable antenna structures. The greater rigidity may facilitate larger antenna structures to be produced, such as 60 feet or more in diameter. Larger antenna structures may increase a gain of the reflector antenna system, which may improve signal reception and/or reflection, which may increase coverage areas and signal quality. The greater rigidity may also improve the surface accuracy of the reflector, which may further improve signal reception and/or reflection. The embodiments of the disclosure may also reduce the number of moving components in an expandable antenna. Reducing the moving parts may result in a more robust design with high reliability. Reducing the moving parts may also reduce the stowed volume and/or weight of the antenna structure. In aerospace applications, where volume and weight of the associated vehicle are restricted, reducing the volume and space requirements of the antenna structure may result in the vehicle being able to carry additional components and/or may facilitate a larger expandable antenna structure.
The embodiments of the disclosure described above and illustrated in the accompanying drawing figures do not limit the scope of the invention, since these embodiments are merely examples of embodiments of the invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of this disclosure. Indeed, various modifications of the disclosure, in addition to those shown and described herein, such as alternative useful combinations of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims and their legal equivalents.