Cheng J.-F.,PLA Air Force Aviation University |
Dong X.-M.,PLA Air Force Aviation University |
Chen A.-H.,PLA Air Force Aviation University |
Dong Z.,PLA Military Representative Office in Shenyang Aircraft Industries Group Co.
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2012
For a type of Takagi-Sugeno (T-S) fuzzy systems with norm-bounded parameter uncertainties, the problem of designing a guaranteed cost robust flight control law with constraints is researched allowing for the guarantee of the various performance indexes and variable constraints via the state feedback parallel-distributed compensation. A constraint fuzzy optimal guaranteed cost control theorem is proposed through modification of the input, output and state linear matrix inequality (LMI). A fuzzy system robust disturbance resistant theorem is also proved with the uncertainty matrix to overcome the parameter perturbation, and the constraint fuzzy optimal guaranteed perturbation immunity theorem is derived on the basis above. Finally, the aircraft T-S fuzzy model is found and the flight control laws satisfying the preceding three theorems are designed respectively. The simulation and comparison are given and the results validate its effectiveness.
Wen C.,Beihang University |
Xu G.-X.,Shenyang Aircraft Design Institute |
Fan L.-W.,PLA Military Representative Office in Shenyang Aircraft Industries Group Co. |
Chen Y.-Z.,Shenyang Aircraft Design Institute
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2015
The corrosion behaviors of 20Cr9Ni5Co14 ultra high strength steel (USS) were studied by the electrochemical polarization methods (potentiodynamic polarization, linear polarization and cyclic polarization technologies) and alternating current impedance spectrum methods in different corrosion conditions, and after polarization the corrosion morphologies were characterized by Scanning Electron Microscopy (SEM). The results showed that the passivation phenomenon of 20Cr9Ni5Co14 steels appeared in 3.5 wt.% NaCl solution while disappeared with the increase of NaCl concentration. The corrosion current also reduced from 8.223×10-7 A/cm2 to 1.129×10-7 A/cm2 with the increase of NaCl concentration. The passivation and transpassivation potentials of 20Cr9Ni5Co14 steels increased with the increase of hydrogen ion concentrations. When the pH value was higher than 3, the corrosion product film had excellent corrosion resistancewhich led the electrochemical polarization step as a dominated step, while the pH value decreased to 2, the corrosion products dissolution rate was fast, the corrosion rate of the interface of the metal surface and the solution was also fast, thus the polarization caused by concentration differences became the dominated step. Corrosion morphology studies showed that the corrosion of 20Cr9Ni5Co14 steels in the polarization process oriented from pitting corrosion, which leads to the reduction of corrosion resistance. ©, 2015, Northeastern University. All right reserved.
Wang Y.,Academy of Armored force Engineering |
Zhu Y.,Academy of Armored force Engineering |
Huang Y.,Academy of Armored force Engineering |
Zhao Q.,63961 Army |
And 2 more authors.
Jixie Qiangdu/Journal of Mechanical Strength | Year: 2014
Analysis on fracture failure of suspension spring of an heavy vehicle was carried out by the means of observation of fracture surface, physical chemistry test, analysis of process technology and servicing conditions, and the reason of fracture was found. The analysis indicates that, because of the contact concept between the bearing coil and the first active coil was used, the both coils discussing in previous sentence would collide and wear, then phosphate layer and painting were worn out, and the wire of spring was attacked by corrosion. Then, the fatigue crack was generated by the stress concentration induced by the corrosion pits, and propagated slowly under the main principle stress, finally, the spring failed in the model of normal tensile fracture. In the end, some recommendations were put forward in order to avoid this type of fracture.
Qiao Y.-L.,AVIC Shenyang Aircraft Corporation Ltd. |
Sha C.-P.,AVIC Shenyang Aircraft Corporation Ltd. |
Dong Y.,PLA Military Representative Office in Shenyang Aircraft Industries Group Co. |
Liu B.,AVIC Shenyang Aircraft Corporation Ltd.
Yejin Fenxi/Metallurgical Analysis | Year: 2016
The potentiodynamic polarization scanning of eletrodeposited chromium electrolyte was conducted with three-electrode system using spectroscopically pure graphite electrode as working electrode. Based on the variation relationship between reducing peak current and oxidizing peak current of mass concentration of electro-active materials on graphite electrode surface, the determination method of Cr6+ and Fe2+ in eletrodeposited chromium electrolyte by linear sweep voltammetry was established. The results showed that the optimal experimental conditions were as follows: the scanning rate was 50-60 mV/s, the pH was 2.0, and the testing temperature was 20℃. Cr6+ was reduced at 0.43 V (vs. saturated calomel electrode, SCE). The mass concentration of Cr6+ in range of 2-14 g/L showed linearity to the reducing peak current, and the correlation coefficient of linear regression equation was R2=0.999. Fe2+ was oxidized at 0.52 V (vs. SCE). The mass concentration of Fe2+ in range of 5-15 g/L showed linearity to the oxidizing peak current, and the correlation coefficient of linear regression equation was R2=0.998.The proposed method was applied to the determination of Cr6+ and Fe2+ in actual chromium electrolyte. The relative standard deviations (RSD, n=10) were between 1.1% and 1.3%. The determination results were compared with those obtained by ammonium ferrous sulfate titration for Cr and atomic absorption spectrometry for Fe. The consistency was good. © 2016, CISRI Boyuan Publishing Co., Ltd. All right reserved.
Zhou X.,Shenyang Aircraft Design Institute |
Sun X.,Shenyang Aircraft Design Institute |
Bing Y.,PLA Military Representative Office in Shenyang Aircraft Industries Group Co. |
Yang B.,Nanjing University of Aeronautics and Astronautics
Shuju Caiji Yu Chuli/Journal of Data Acquisition and Processing | Year: 2014
The information of drogue containing position and size are used to establish Kalman filter equations. The model parameters are set considering drogue's motion features in refueling process and the object occlusion coefficient is introduced to complete the parameters' adaptive adjustment. The next-time states of moving drogue are estimated by the model and the estimation is corrected by observation. The experimental results show that the algorithm can track the drogue stably in work distances. When non-target moving objects appear in the images or the drogue is obscured, the algorithm still has the ability of continuous tracking. ©, 2014, Nanjing University of Aeronautics an Astronautics. All right reserved.