This project is focused on the development of a high-force, high-speed piezoelectric actuator for control of a 2-inch (≈5-cm) isolation valve application in a cryogenic vacuum environment. The piezo motor actuators on the two cryogenic isolation valves were successfully tested at NASA MSFC at 300 to 400 psi (≈2.07 to 2.76 MPa) flow pressure. The testing did not expose the piezo elements to temperatures below 0 °C. Iceramic piezo material has not failed under cryogenic testing to the date of this reporting.

Acceptance testing was performed by NASA JSC. The actuator provides a compact, high-force, high-endurance piezo element preload mechanism for cryo/vacuum environments. It offers a high-coefficient- of-friction, high-endurance friction interface material for cryo/vacuum environments. The system features a compact, replaceable, strain-relieved wire routing scheme, and precision machining and interfacing of multiple part surfaces to less than 0.0002 inch (≈5 μm). Other characteristics include pseudo-sine wave, high-current, high-voltage, high-frequency piezo drive electronics; and cryo cycle testing with high-power waveform of various types of piezo ceramic materials for use in the cryogenic/ vacuum application.

The use of a cryogenic-environment, reliable piezo ceramic material provides a relatively higher level of measured reliability versus other polymer-coated piezoelectric ceramics. Commercial applications exist in fluid valve control for all types of cryogenic fluids. Similarly, the actuators alone may be used for thermally stable adaptive optics, instrumentation control, and latching or kinematic functions.

This work was done by Jacob Collins of Johnson Space Center, and Jeffrey Paine and Patrick McGirt of Dynamic Structures and Materials LLC. MSC-25131-1

NASA Tech Briefs Magazine

This article first appeared in the December, 2015 issue of NASA Tech Briefs Magazine.

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