Research for reliability of the actuator of fast reflector based on FMECA

China is now building the largest single dish radio telescope in the world in Guizhou province, namely the Five-hundred-meter Aperture Spherical radio Telescope (FAST). As the most important mechanism of the active reflector, more than 2200 actuators are used for the active deformation of the FAST reflector. Due to the amount of actuators used, the reliability study on the actuators is of great significance. The main purpose of this paper is to qualitatively analyze the reliability of the actuator using Failure Mode Effects and Criticality Analysis (FMECA) method. The design of the actuator with a complex hybrid mechanism is described. After analyzing the failure modes of the actuator, the chart of actuator failure mode and effect analysis for the actuator will be given. The criticality degree for the actuator will be analyzed and calculated. Potential weak points of the actuator can then be found out. To provide quantified reference to reduce these failures, further calculation will be carried out on criticality of the actuator in different severe degrees. The study in this paper provides a analytical basis for the reliability based optimum design of the actuator for FAST.