Reliability Evaluation of Key Hydraulic Components for Actuators of FAST Based on Small Sample Test

The five-hundred meter aperture spherical radio telescope (FAST) is China's major science and technology infrastructure project. Upon completion, this telescope will be considered the largest single-dish radio telescope in the world. As main active mechanism of FAST, 2225 hydraulic actuators are used for adjusting the reflectors. The reliability of hydraulic actuators is the most critical matter. This paper applies the reliability theory and reliability test method into large project for the first time. Firstly, a parallel energy-saving method and equipment to test the two components of the actuators for FAST are designed. Secondly, reliability model based on small sample test is used to perform the best linear unbiased estimation of the test data. Average impact lifetime of the sampled gear pump and the sampled relief valve in their working condition are calculated. Finally, the results show that the lifetime request of the sampled gear pump and the sampled relief valve for hydraulic actuator of FAST are satisfied. The research method has guiding significance to the reliability study of key hydraulic components for similar hydraulic systems.