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This paper presents an observer-based baseline flight control law designing approach with passive fault tolerant control (PFTC) capability for aircraft which suffers from vertical tail damage. Considering vertical tail damage to a certain extent, an observer-based control scheme is synthesized into traditional baseline control framework. The baseline control law is designed based on the observation...
In view of the strongly nonlinear characteristic of electro-hydraulic servo system (EHSS), this paper aims to conduct nonlinear ordinary differential equation (ODE) parameter identification of white-box model based on the knowledge of part of the system information so as to get the accurate nonlinear model that can meet the actual needs. By establishing the state space model of the hydraulic system...
As an important component of the vacuum system, the performance of Roots Pump affects the reliability of the system. This paper selects the rotor wear fault mode as the research object, based on the establishment of Roots Pump's basic model, through the analysis on the failure mechanism, models the leakage, and finally establishes the Roots Pump's performance degradation model of leakage caused by...
This paper establishes mathematical model of radial lip seals and flow factors method are used to show the influence of aging in oil and wear on such features as pumping rate, friction torque. The root mean square (RMS) roughness is a vital parameter to predict the sealing performance in the model of lip seals. And the RMS of the elastomeric material is intensely influenced by the time of aging in...
Mechanical seals are used to prevent leakage of hydraulic fluid in the seal cavity, and in the meantime prevent entry of external contaminants. It is widely used in hydraulic pumps, hydraulic motors and other rotating hydraulic devices. And therefore there are many different designs for mechanical seals to meet specific applications. Due to its superior performance, mechanical seals have been widely...
Oil debris monitoring (ODM) is a significant technique for contaminate particle detection in real time for hydraulic systems. Current radial magnetic oil debris detector only provide the acceptable debris detection accuracy under the single particle. When two or more debris particles are generated in the oil and they pass through the debris sensor, the aliasing effects occur in detection signal and...
This paper presents a model reference adaptive control for dissimilar dual redundant actuation system that is a combination of hydraulic and electro-hydrostatic actuator. A modified form of MIT rule, called the normalized MIT rule, has been given to find the controller parameters. The reference model is designed on the base of dynamics characteristics of HA. Normalized MIT rule updates the parameter...
Product Realization: A Comprehensive Approach is based on selected papers presented at the International Conference on Comprehensive Product Realization 2007 (ICCPR2007). The extended papers will provide the opportunity for scholars from all around the world to discuss their academic programs, identify research opportunities, and initiate joint research programs in the area of comprehensive product...
Dissimilar redundant actuation system has high reliability because of getting rid of central hydraulic power and avoiding common cause failures, which conform to the development trend of future actuation systems in large civil aircraft. Despite these advantages, force fighting widely exists in dissimilar redundant actuation systems due to the different driving principle and system parameters of different...
Based on Empirical Mode Decomposition (EMD) and feature energy entropy, a method for the fault severity recognition of piston pumps is proposed in this paper. The discharge pressure signals of piston pumps are decomposed into a series of Intrinsic Mode Function (IMF) components by using EMD. Then, some useful IMF components are selected by calculating correlation coefficient between the signal reconstructed...
To address the impact of a high-speed internal turbine-gearbox anomalies, it is important to perform torsional vibration analysis of the gearbox. This paper illustrates a developed transfer matrix method to investigate the torsional vibration mechanisms of a gearbox equipment. An inertial reference frame is introduced into the procedure of discretizing the system and building the lumped parameters...
For the gradual faults of the new hybrid collaboration actuation system composed by hydraulic actuator(HA) and electro-hydraulic actuator(EHA), this paper develops a control law with the function of passive fault-tolerant. In this study, HA is active and EHA is passive, and the gradual faults such as leakage and flow changes are characterized as uncertainties of the system, then an equivalent model...
Besides the hardware/software failure of switched Ethernet, the capability of data transmission affects its performance and reliability. After summarizing the influence factors of Ethernet service capability, this paper focuses on the time delay oriented reliability model and analysis method. Based on the operational mechanism analysis of Avionics Full Duplex Switched Ethernet (AFDX), this paper emphasizes...
Aging is the main failure mechanism of rubber seal ring during the storage period for hydraulic actuator. Considering the influence of temperature, oxygen concentration and mechanical force, this paper presents an integrated aging model based on the volume variation, elasticity modulus and molecular reconfiguration. With the slot flow theory, we get the relationship between the material structure...
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