This paper develops a new method, named E-Bayesian estimation method, to estimate the reliability parameters. The E-Bayesian estimation method of the reliability are derived for the zero-failure data from the product ...This paper develops a new method, named E-Bayesian estimation method, to estimate the reliability parameters. The E-Bayesian estimation method of the reliability are derived for the zero-failure data from the product with Binomial distribution. Firstly, for the product reliability, the definitions of E-Bayesian estimation were given, and on the base, expressions of the E-Bayesian estimation and hierarchical Bayesian estimation of the products reliability was given. Secondly, discuss properties of the E-Bayesian estimation. Finally, the new method is applied to a real zero-failure data set, and as can be seen, it is both efficient and easy to operate.展开更多
A novel electro-hydrostatic actuator （EHA） for active vibration isolation has been designed, modelled and tested. The EHA consists of a brushless DC motor running in oil and integrated with a bidirectional gear pu...A novel electro-hydrostatic actuator （EHA） for active vibration isolation has been designed, modelled and tested. The EHA consists of a brushless DC motor running in oil and integrated with a bidirectional gear pump, driving a hydraulic cylinder. The actuator is designed to be integrated into a flexible strut connecting a helicopter rotor hub and fuselage, to provide isolation at the dominant rotor vibration frequency of around 20 Hz. The resonant frequency of the EHA is tuned to provide some passive vibration isolation. Active control increases the isolation performance by compensating for damping losses, and provides isolation over a broader range of frequencies. Tests on a prototype demonstrated a four-fold reduction of the root-mean-square transmitted force and a near elimination at the fundamental frequency. The advantages of the resonant EHA are a wider range of operating frequencies than a purely passive system, and lower power consumption than a purely active system.展开更多
基金Supported by the Fujian Province NSFC(2009J01001)
文摘This paper develops a new method, named E-Bayesian estimation method, to estimate the reliability parameters. The E-Bayesian estimation method of the reliability are derived for the zero-failure data from the product with Binomial distribution. Firstly, for the product reliability, the definitions of E-Bayesian estimation were given, and on the base, expressions of the E-Bayesian estimation and hierarchical Bayesian estimation of the products reliability was given. Secondly, discuss properties of the E-Bayesian estimation. Finally, the new method is applied to a real zero-failure data set, and as can be seen, it is both efficient and easy to operate.
文摘A novel electro-hydrostatic actuator （EHA） for active vibration isolation has been designed, modelled and tested. The EHA consists of a brushless DC motor running in oil and integrated with a bidirectional gear pump, driving a hydraulic cylinder. The actuator is designed to be integrated into a flexible strut connecting a helicopter rotor hub and fuselage, to provide isolation at the dominant rotor vibration frequency of around 20 Hz. The resonant frequency of the EHA is tuned to provide some passive vibration isolation. Active control increases the isolation performance by compensating for damping losses, and provides isolation over a broader range of frequencies. Tests on a prototype demonstrated a four-fold reduction of the root-mean-square transmitted force and a near elimination at the fundamental frequency. The advantages of the resonant EHA are a wider range of operating frequencies than a purely passive system, and lower power consumption than a purely active system.
