The Design and Test of a Cryogenic Micro-Displacement Actuator

Taking the polar astronomical telescope as application background, a cryogenic micro-displacement actuator is designed and then tested at room temperature and low temperature environment respectively. Performance parameters of this actuator is acquired. Three kinds of structural forms of long travel high-accuracy micro-displacement actuator are analyzed; the displacement scaling is chosen as the basic structure of this cryogenic micro-displacement actuator. Cryogenic step motor is employed as the drive element, and the screw drive mechanism which contains specific anti-backlash structure is selected as the displacement scaling mechanism. This design develops a micro-displacement actuator which maintains satisfactory qualities such as high stiffness, low temperature resistance, compact structure and good leakproofness. Performance tests are also carried out. Test results indicate that the cryogenic micro-displacement actuator can achieve the step accuracy of 1 μm±0.082 μm at ambient temperature, and its load capacity meets the design requirements; meanwhile, the cryogenic micro-displacement actuator can achieve the step accuracy of 2 μm±0.404 μm at low temperature. This cryogenic micro-displacement actuator will provide important technical support for the construction of the splicing polar astronomical telescope.