http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Changsheng Gao (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Effect of Homogenisation Temperature on the Microstructure and Microhardness of As-Cast H13 Steel
Yahui Han,Changsheng Li,Shuai He,Cairu Gao,Shuaishuai Chen,En Li 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.3
This study determined that the homogenisation temperature range of experimental as-cast H13 steel was from 1150 to1230 °C, whilst the effect of homogenisation temperature range on the microstructural evolution and microhardness wastested. The enrichment of alloying elements in the dendrite segregation region decreased the solidus temperature of matrix,whose total content determined the maximum homogenisation temperature. The secondary dendrite branches were mostdissolved at 1150 °C, and overheating appeared at 1230 °C in the segregation region. Moreover, the primary carbidesunderwent shrinking, passivation, fragmentation and dissolution. The secondary carbides M23C6and M6Cwere formed atthe interfaces of MC/γ and M7C3/γ, respectively. As the homogenisation temperature increased from 1150 to 1230 °C, thevalue of microhardness gradually decreased from 771 to 740 HV. Nevertheless, the standard deviation value decreased firstand then increased, which reached the minimum 32 HV at 1200 °C, indicating that the hardness homogeneity was the best.
-
Closed-Loop Bifurcation Analysis for a Novel Moving Mass Flight Vehicle
Zhitao Liu,Changsheng Gao,Jianqing Li,Wuxing Jing 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.4
In this paper, nonlinear dynamics properties regarding a novel moving mass flight vehicle with large mass ratio are investigated based on bifurcation theory and continuation methods. Of particular interest is the impact of variation of command angle-of-attack and moving mass parameters on the controlled system. The nonlinear longitudinal dynamics model is established and the controller is designed using Immersion and Invariance method. Bifurcation analysis is conducted both from the prospective of static bifurcation and dynamical bifurcation, results of the closed-loop system are compared with the uncontrolled case. Numerical results obtained from bifurcation diagrams indicate that although the introduction of control system is capable of eliminating unstable regions caused by the variation of moving mass parameters, the change of command angle-of-attack still lead to Hopf bifurcation. Furthermore, analysis of limit cycle branch reveals the consecutive birth of Limit Point of Cycle bifurcation (LPC), then based on which a more detailed nonlinear dynamics process of the closed-loop system is analyzed.
-
Pengxin Wei,Changsheng Gao,Wuxing Jing 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.1
This paper presents a composite Bank-To-Turn (BTT) control mode with a moving mass and non-redundant Reaction Control System (RCS) for a hypersonic unpowered glider vehicle. This type of control mode can not only preclude the aerodynamic control surfaces ablation, but also optimize the internal space of flight vehicle. The identification of the aerodynamic coefficients for gliders under the novel control mode remains an important research focus. As a key part of system identification, input design greatly affects the identification results. Taking into account the flight characteristics and composite control strategy, the longitudinal dynamic characteristics considering the cubic nonlinearities of hypersonic glider are analyzed and the motion form of internal moving mass is designed based on multi-sine input method. The identifiability and identifiability degree of each longitudinal parameter are evaluated using singular value decomposition of the measure matrix. Simulation results demonstrate that the designed input form improves the accuracy of the estimated parameters, and showthe identification order from the most identifiable parameter to the least identifiable parameter.
-
Dynamics and Adaptive Sliding Mode Control of a Mass-Actuated Fixed-Wing UAV
Xiaoqi Qiu,Mingen Zhang,Wuxing Jing,Changsheng Gao 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.4
Compared with UAVs controlled by aerodynamic surfaces, mass-actuated UAVs have higher aerodynamic efficiency and better stealth performance. This paper focuses on the dynamics and attitude control of a mass-actuated fixed-wing UAV (MFUAV) with an internal slider. Based on the derived mathematical model of the MFUAV, the influence of the slider parameters on the dynamical behavior is analyzed, and the ideal installation position of the slider is given. Besides, it is revealed that the mass-actuated scheme has a higher control efficiency for low-speed UAVs. To deal with the coupling, uncertainty and disturbances in the dynamics, an adaptive sliding mode controller based on fuzzy system, RBF neural network and sliding mode control are proposed. The RBF neural network uses the minimum parameter learning method to improve its learning speed. It is proved by the Lyapunov method that the proposed controller is ultimately uniformly bounded. Finally, the simulation verifies the effectiveness and robustness of the controller.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
