HIGH-ACCURACY CRYOGENIC LINEAR ACTUATOR

THIS INVESTIGATION WILL BE DIRECTED TOWARDS THE DEVELOPMENT OF A HIGH-ACCURACY CRYOGENIC LINEAR ACTUATOR. ONE OF THE MOST STRAIGHTFORWARD APPROACHES TO THE PROBLEM OF LINEAR MOTION AT CRYOGENIC TEMPERATURES USES A ROTATING STEPPER MOTOR AND LEADSCREW ARRANGEMENT TO ACHIEVE THE DESIRED RESOLUTION AND ACCURACY. TO DATE, THESE EFFORTS HAVE BEEN UNABLE TO PRODUCE HIGH-ACCURACY OVER A REASONABLE LIFETIME, PRIMARILY DUE TO THE BEARING DESIGNS. TO MEET THE REQUIREMENTS OF THIS SOLICITATION TOPIC, THESE BEARINGS MUST BE UNLUBRICATED, LOW WEAR, AND PRODUCE VERY FEW PARTICLES SO THAT A HIGH-VACUUM IS MAINTAINED. A BEARING DESIGN HAS ALREADY BEEN DEVELOPED AND TESTED WHICH SHOWS MUCH PROMISE FOR THE PRESENT APPLICATION. FURTHERMORE, CRYOGENIC STEPPER MOTORS WITH BOTH NORMAL AND SUPERCONDUCTING WINDINGS HAVE BEEN TESTED IN OUR LABORATORY TO TEMPERATURES OF 2.0K WITH SUCCESS. WE PROPOSE AN EFFORT TO DESIGN, FABRICATE A MODEL, AND TEST A CRYOGENIC STEPPER MOTOR/LEADSCREW ASSEMBLY WHICH MEETS OR EXCEEDS THE REQUIREMENTS FOR SPEED, ACCURACY, REPEATABILITY, AND RESOLUTION. ADDITIONALLY, LOW-POWER DESIGNS WILL BE INVESTIGATED TO CONSERVE CRYOGENS IN APPLICATIONS WHERE COOLING IS LIMITED. POSITION AND SPEED READOUTS WILL BE ADDRESSED, AS WELL AS THE VOLUME CONSTRAINTS (<200MM CUBE).