Claims
- 1. An apparatus for positioning a moveable structure relative to a support structure, comprising:
a moveable structure; a support structure; a compliant support disposed between the moveable structure and the support structure, the compliant support biasing the moveable structure away from the support structure; and three shape memory alloy actuators, the three shape memory alloy actuators symmetrically arranged about the compliant support wherein each shape memory alloy actuator is attached to the moveable structure and the support structure whereby selectively activating the three shape memory alloy actuators provides two degrees of freedom of movement for the moveable structure relative to the support structure.
- 2. The apparatus for positioning a moveable structure according to claim 1 wherein the three shape memory alloy actuators are provided by stringing a single strand of shape memory alloy wire between the moveable structure and the support structure such that each shape memory alloy actuator comprises a first segment disposed between a first connection point on the support structure and a connection point on the moveable structure and a second segment disposed between a second connection point on the support structure and the connection point on the moveable structure.
- 3. The apparatus for positioning a moveable structure according to claim 2 wherein each of the first segment and second segment on each of the three shape memory alloy actuators is seperably actuable by a control circuit.
- 4. The apparatus for positioning a moveable structure according to claim 1 wherein each shape memory alloy actuator has a single shape memory alloy wire connected to the support structure and the moveable structure.
- 5. The apparatus for positioning a moveable structure according to claim 4 wherein each shape memory alloy actuator is connected to a control circuit for selectively powering the shape memory alloy actuators.
- 6. The apparatus for positioning a moveable structure according to claim 5 wherein the control circuit is a voltage controller.
- 7. The apparatus for positioning a moveable structure according to claim 5 wherein the control circuit is a silicon controlled rectifier.
- 8. The apparatus for positioning a moveable structure according to claim 1 wherein the moveable structure comprises a mirror.
- 9. An apparatus for positioning a mirror, consisting of:
a mirror; a support structure; a compliant support disposed between the mirror and the support structure; and three linear shape memory alloy actuators, each shape memory alloy actuator connected to the mirror and the support structure and being disposed about the compliant support such that selective activation of individual linear shape memory alloy actuators produces two degrees of freedom for the movement of the mirror.
- 10. An apparatus for positioning a mirror according to claim 9 wherein the three linear shape memory alloy actuators are symmetrically positioned about the compliant support.
- 11. An apparatus for positioning a mirror according to claim 9 further comprising a power supply capable of selectively powering the three linear shape memory alloy actuators.
- 12. An apparatus for positioning a mirror according to claim 9 wherein the linear shape memory alloy actuators is formed from a single strand of shape memory alloy wire.
- 13. An apparatus for positioning a minor according to claim 9 wherein the shape memory alloy actuators have at least one component selected from the group consisting of: titanium and nickel (TiNi); copper, aluminum and nickel (CuAlNi); and titanium, nickel and palladium (TiNiPd).
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims benefit under 35 USC 119(e) to U.S. Provisional Patent Application Ser. No. 60/378,619 filed May 6, 2002, entitled “Actuator for Two Angular Degrees of Freedom”. The above application is incorporated herein by reference in its entirety.
Provisional Applications (1)
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Number |
Date |
Country |
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60378619 |
May 2002 |
US |