Evaluation of Concept for a Laser Acquisition and Tracking Subsystem
Final rept. Jun 1972-Apr 1973
BALL BROS RESEARCH CORP BOULDER CO
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The program objective was to evaluate the starting and running friction characteristics of bearings rotating at 0.001 - 1.0 degreesecond and to determine the pointing accuracy that can be achieved on a bearing supported gimbal system. The bearing tests measured the friction of bearings with pitch diameters of 0.25, 1.4 and 2.6 inches, using liquid and dry film lubricants, at high and low temperatures, and with various axial preloads. The running friction results were generally lower than predicted, varying from less than detectable to 0.9 ounce inches. The starting friction tests showed that the bearings have a spring-like characteristic when small torque levels are applied, that the starting friction levels were much lower than expected 0.03 ounce inch, and that a starting friction peak larger than the low speed running friction level does not exist. The pointing accuracy tests were performed on a single axis gimbal which was controlled by a conventional servo system. Tests were run on the repeatability of the system in attaining null, the ability to point while the gimbal housing was rotating at 1 degsecond, and the effects of disturbances on the system. The tests showed that pointing accuracies in the range of 10 - 35 microradian can be achieved on bearing supported system and that the bearings are not the limiting cause of errors.
- Lasers and Masers
- Machinery and Tools