Research On Reliability Growth Of FAST Hydraulic Actuator Hydraulic Integrated Pipeline System

Five-hundred-meter Aperture Spherical Radio Telescope(hereinafter referred to as FAST)is the largest and most sensitive single-aperture radio astronomical telescope in the world.44 pulsars have been identified so far.One of the three innovations of FAST is to adjust the angle of reflector by using the expansion of hydraulic actuator group system.Because of the working requirement of 24 hours a day,the reliability of a single hydraulic actuator is highly required when adjusting the angle of the reflector.Therefore,in order to ensure the long-term stability of the reflector,it is necessary to study the reliability growth of FAST hydraulic actuator.Firstly,aiming at the hydraulic actuators with individual faults,a reliability test-bed was built,and the reliability acceleration test was carried out on the FAST hydraulic actuator test prototype to find out the causes of the faults.Aiming at the causes of the failure,the reliability optimization design of the hydraulic integrated pipeline system is carried out.The feasibility of the optimization design is verified by the finite element analysis software,and the reliability optimization design scheme is processed.Then,according to the reliability growth research of similar products,a suitable reliability growth test plan is made for the test prototype mechanism after the reliability optimization design of hydraulic integrated pipeline system.Then,according to the principle of finding problems and continuing optimization,reliability growth test is carried out on the hydraulic actuator test prototype after reliability optimization design,in order to meet the requirements of reliability growth plan,and the type B failure data in reliability growth test are obtained.Finally,based on class B failure data in reliability growth test,the reliability growth model of hydraulic actuator test prototype after reliability optimization design of hydraulic integrated pipeline system is obtained by linear regression in double logarithmic coordinates with least square method.Based on AMSAA model,the unbiased estimation and confidence interval of MTBF at the time of truncation of reliability growth test are obtained,which verifies that the reliability growth test meets the planning requirements.It is of great significance for ensuring the long-term and reliable operation of FAST hydraulic actuator group system to provide optimal design method and reliability growth test method for subsequent hydraulic actuators with individual faults.