Multifunctional structures for attitude control
View Patent ↗A structure for changing the attitude of a spacecraft is provided including an elongated member and a plurality of actuators coupled to the elongated member. The elongated member is coupled to the spacecraft. The elongated member has a length and an angular position relative to an axis. The plurality of actuators are configured to deflect the angular position of the elongated member relative to the axis and to alter the length of the elongated member.
1 . A structure for changing an attitude of a spacecraft, comprising:
an elongated member coupled to the spacecraft, the elongated member having a length and an angular position relative to an axis passing through the spacecraft; and
at least one actuator coupled to the elongated member,
wherein the at least one actuator is configured to deflect the angular position of the elongated member relative to the axis, and to alter the length of the elongated member, wherein the deflection of the angular position of the elongated member relative to the axis and the alteration of the length of the elongated member together move the spacecraft though a rotation cycle, and wherein the rotation cycle results in a secular angular change of the spacecraft.
2 . The structure of claim 1 , wherein the at least one actuator comprises an array of piezoelectric elements embedded within the elongated member and extending along the length of the elongated member.
3 . The structure of claim 1 , wherein the at least one actuator comprises a piezoelectrically operated lever mechanism embedded within the elongated member.
4 . The structure of claim 3 , wherein the piezoelectrically operated lever mechanism comprises a plurality of stacked struts and a plurality of piezoelectric elements, wherein each of the struts extend from a first side to a second side, each of the struts are coupled adjacent struts at a plurality of joints formed alternatingly on the first side and the second side, and each of the plurality of piezoelectric elements are positioned proximate to one of the plurality of joints.
5 . The structure of claim 4 , wherein each of the stacked struts is made from a strong metal capable of withstanding high stress.
6 . The structure of claim 5 , wherein the strong metal capable of withstanding high stress comprises ANSI-4030 steel.
7 . The structure of claim 1 , wherein the at least one actuator comprises a first actuator arranged on a first side of the elongated member, and a second actuator arranged on an opposing second side of the elongated member.
8 . The structure of claim 1 , wherein the elongated member comprises a geometric prism having a plurality of corners and a base coupled to the spacecraft, wherein the at least one actuator is positioned proximate to one of the plurality of corners.
9 . The structure of claim 1 , wherein the at least one actuator comprises a spatially distributed strain actuator.
10 . The structure of claim 1 , wherein the at least one actuator comprises at least one of: a piezoelectric actuator, an electromagnetic actuator, a hydraulic actuator, a pneumatic actuator, a thermal actuator, a magnetic actuator, or a mechanical actuator.
11 . The structure of claim 1 , wherein the rotation cycle is performed at a rate that is at or around a natural frequency of the elongated member.
12 . The structure of claim 1 , wherein the elongated member comprises an empty rectangular frame shape.
13 . The structure of claim 1 , wherein the elongated member comprises an ellipsoidal shape.
14 . The structure of claim 1 , wherein the elongated member comprises a complex polyhedron shape.
15 . The structure of claim 1 , wherein the at least one actuator comprises a mechanical actuator.
16 . The structure of claim 15 , wherein the mechanical actuator comprises an electric motor.
17 . The structure of claim 15 , wherein the mechanical actuator comprises a voice coil.
18 . The structure of claim 1 , wherein the at least one actuator comprises a hydraulic actuator or a pneumatic actuator.
19 . The structure of claim 1 , wherein the rotation cycle comprises:
an initial deflection of the elongated member from an initial angular position to an altered angular position relative to the axis, wherein the spacecraft undergoes an initial angular change;
a compression of the elongated member from an initial length to an altered length, wherein the compression of the elongated member decreases a mass moment of inertia of the elongated member; and
a second deflection of the elongated member from the altered angular position to the initial angular position, wherein the spacecraft undergoes a subsequent angular change toward the initial position of the spacecraft, wherein the subsequent angular change of the spacecraft back toward the initial position is less than the initial angular change of the spacecraft during the initial deflection of the elongated member, and wherein the secular angular change of the spacecraft comprises a difference between the initial angular change and the subsequent angular change.
20 . The structure of claim 19 , wherein the rotation cycle comprises:
after completing the second deflection of the elongated member, adjusting the elongated member from the altered length back to the initial length.