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Yang B.,University of Shanghai for Science and Technology | Yang B.,Northwestern Polytechnical University | Huang B.,Northwestern Polytechnical University | Huang B.,Beijing System Design Institute of Electro mechanic Engineering | And 3 more authors.
Yuhang Xuebao/Journal of Astronautics | Year: 2015

For the wide operating range, the performance evaluation of rocket based combined cycle (RBCC) engine, such as thrust, specific impulse and combustion efficiency, is difficult to directly calculate by key parameters in-situ and online measurements. In this paper, a non-intrusive laser spectroscopy method based on tunable diode laser absorption spectroscopy (TDLAS) is proposed to measure the temperature, species concentration and velocity of burned gas simultaneously. The time-division multiplexing-wavelength scanning TDLAS system is designed to obtain the spectrums near (7444.352+7444.371)/7185.597 cm-1 of exhaust gas in RBCC ground test. And the gas temperature, H2O species concentration, and velocity parameters are determined. With the longitudinal distributions of parameters which obtained by numerical method, the thrust, specific impulse and combustion efficiency of RBCC ground test can be directly caculated by the TDLAS measurements. It can provide a reference for the optimization of combustion organization and engine structure. © 2015, Editorial Dept. of JA. All right reserved.

Du J.,Beihang University | Du J.,Beijing System Design Institute of Electro mechanic Engineering | Wang S.,Beihang University | Zhang H.,Purdue University
Mechanical Systems and Signal Processing | Year: 2013

Efficient diagnosis is very important for improving reliability and performance of aircraft hydraulic piston pump, and it is one of the key technologies in prognostic and health management system. In practice, due to harsh working environment and heavy working loads, multiple faults of an aircraft hydraulic pump may occur simultaneously after long time operations. However, most existing diagnosis methods can only distinguish pump faults that occur individually. Therefore, new method needs to be developed to realize effective diagnosis of simultaneous multiple faults on aircraft hydraulic pump. In this paper, a new method based on the layered clustering algorithm is proposed to diagnose multiple faults of an aircraft hydraulic pump that occur simultaneously. The intensive failure mechanism analyses of the five main types of faults are carried out, and based on these analyses the optimal combination and layout of diagnostic sensors is attained. The three layered diagnosis reasoning engine is designed according to the faults' risk priority number and the characteristics of different fault feature extraction methods. The most serious failures are first distinguished with the individual signal processing. To the desultory faults, i.e., swash plate eccentricity and incremental clearance increases between piston and slipper, the clustering diagnosis algorithm based on the statistical average relative power difference (ARPD) is proposed. By effectively enhancing the fault features of these two faults, the ARPDs calculated from vibration signals are employed to complete the hypothesis testing. The ARPDs of the different faults follow different probability distributions. Compared with the classical fast Fourier transform-based spectrum diagnosis method, the experimental results demonstrate that the proposed algorithm can diagnose the multiple faults, which occur synchronously, with higher precision and reliability. © 2012 Elsevier Ltd.

Liu D.,Harbin Institute of Technology | Luo Y.,Beijing System Design Institute of Electro mechanic Engineering | Liu J.,Carleton University | Peng Y.,Harbin Institute of Technology | And 2 more authors.
Neural Computing and Applications | Year: 2013

The lithium-ion battery cycle life prediction with particle filter (PF) depends on the physical or empirical model. However, in observation equation based on model, the adaptability and accuracy for individual battery under different operating conditions are not fully considered. Therefore, a novel fusion prognostic framework is proposed, in which the data-driven time series prediction model is adopted as observation equation, and combined to PF algorithm for lithium-ion battery cycle life prediction. Firstly, the nonlinear degradation feature of the lithium-ion battery capacity degradation is analyzed, and then, the nonlinear accelerated degradation factor is extracted to improve prediction ability of linear AR model. So an optimized nonlinear degradation autoregressive (ND-AR) time series model for remaining useful life (RUL) estimation of lithium-ion batteries is introduced. Then, the ND-AR model is used to realize multi-step prediction of the battery capacity degradation states. Finally, to improve the uncertainty representation ability of the standard PF algorithm, the regularized particle filter is applied to design a fusion RUL estimation framework of lithium-ion battery. Experimental results with the lithium-ion battery test data from NASA and CALCE (The Center for Advanced Life Cycle Engineering, the University of Maryland) show that the proposed fusion prognostic approach can effectively predict the battery RUL with more accurate forecasting result and uncertainty representation of probability density distribution (pdf). © 2013 Springer-Verlag London.

Li J.,Nanjing University of Aeronautics and Astronautics | Wang R.,Beijing System Design Institute of Electro mechanic Engineering | Wang T.,Nanjing University of Aeronautics and Astronautics | Gu S.,Nanjing University of Aeronautics and Astronautics | And 2 more authors.
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2014

To optimize the preparation process of graphene/cyanate ester (CE) composites and improve their toughness, p -phenylenediamine functionalized graphene oxide (GO-PPD) was prepared from graphene oxide (GO). GO/CE-epoxy and GO-PPD/CE-epoxy composites were prepared using CE and epoxy blends (mass ratio is 7∶3) as matrix resin and GO, GO-PPD as addition filler. The chemical structure of GO and GO-PPD were characterized by FTIR and Raman spectroscopy. The solubility of GO and GO-PPD was also checked. GO-PPD can steadily dissolve in such solvents as alcohol with low boiling point and hypotoxicity. Compared with GO, GO-PPD greatly improves the preparation process of its composites. The property investigation shows that both of the introduction of GO and GO-PPD decrease the curing temperature, dramatically increase the mechanical and thermal properties, and increase the dielectric constant and the dielectric loss of the matrix resin obviously. However, the good hot -wet and corrosion resistance are maintained. The properties of graphene/CE-epoxy composites change with the surface chemical property of graphene. Compared with GO, GO-PPD more greatly contributes to the improvement of the mechanical and thermal properties of composites.

Zeng X.-F.,Beijing Institute of Technology | Wang J.-Y.,Beijing System Design Institute of Electro mechanic Engineering | Wang X.-H.,Beijing Institute of Technology
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2013

For hypersonic gliding problem, a gliding guidance approach based on energy and analytical predictor corrector is proposed. In this approach, the gliding guidance is divided into two parts: longitudinal guidance and lateral guidance. In the longitudinal guidance, analytical mathematical formulas of range-to-go and energy, bank angle are established based on quasi-equilibrium gliding condition to analytically predict range-to-go, and then the bank angle magnitude is calculated online through the correct algorithm to satisfy the range-to-go and energy request. An angle of attack adjustment algorithm based on altitude is proposed to achieve quasi-equilibrium gliding and make sure that the terminal altitude and velocity constraints are met. In the lateral guidance, a lateral threshold based on cross range and range-to-go is proposed to determine the sign of bank angle command and control terminal heading error.compared with the traditional numerical predictor-corrector guidance method, the calculation cost of the proposed approach is significantly reduced, and the guidance precision and adaptation are good.

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