Research On Reliability Evaluation Key Components Of Hydraulic Actuator

Five-hundred-meter Aperture Spherical radio Telescope(hereinafter referred to as FAST)which is independently researched and developed by China,becomes one of the world's biggest diameter telescope,Its active reflector system with high sensitivity makes the spherical cap opening Angle reached 110-120°.The actuator is the core power control unit in the FAST,2225 actuators will work together for long continuous time,so the reliability of the hydraulic actuator is the foundation of FAST active reflector system the normal operation.In order to ensure that FAST can run for long periods of time,the actuator must be evaluated for reliability.First,hydraulic actuator of FAST,which is an important part of a reflective surface for tracking and observing objects actively,need to evaluate its reliability.And the hydraulic reliability testing and reliability evaluation methods both at home and abroad were discussed.Based on the FAST actuator system belongs to the integrated structure,the suitable method for analyzing its reliability is proposed.The method includes integrated reliability analysis method(FTF),multi-element parallel accelerated degradation test rig,reliability test which contains the acceleration model,scheme and failure criteria.Then,comprehensive analysis(FTF)was adopted to analyze hydraulic actuators,and the key components of the hydraulic actuator that are the gear pump,relief valve and the hydraulic controlled check valve were quantitatively determined.Then the key components determined were test by using the reliability test method.That provides the basis of reliability assessment For FAST actuatorBased on fitting the performance degradation data of samples with the common performance degradation path models,the performance degradation paths of the key components of hydraulic actuator were researched by a search strategy for the optimal degradation model,the optimal degeneration models of samples were selected by goodnessof-fit search programming.Finally,the experimental data were processed according to the statistical analysis method of Weibull lifetime data,the reliability life distribution model of hydraulic pump was obtained based on the conventional mathematical statistics method and Bayes reliability prediction method.The optimization results were verified by the simulation of the experimental data.The reliability characteristic parameters of the samples were evaluated through the optimized result.