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131.
In this paper, a novel real-time obstacle avoidance method based on Dynamic System(DS), is proposed. The proposed method ensures the impenetrability of multiple convex obstacles by online modulating the original velocity field of the DS. It can be applied to perform obstacle avoidance in the state space of the DS with both autonomous and non-autonomous DS-based controllers. While realizing the obstacle avoidance, the equilibrium points of the original DS can be saved. The modulation matrix form ... 相似文献
132.
Phased-Mission Systems(PMS) are widely applied in aerospace, telecommunication and intelligent systems for multiple, consecutive and non-overlapping phases of missions. The phasedependent stresses and system structure cause some difficulties to the reliability analysis of PMSs.In this paper, we analyze the physical isolation effects on the degradation speeds and across-phase damage accumulations of failure mechanisms. And, some corresponding reliability and unreliability formulas are derived. Be... 相似文献
133.
Zong Xia JIAO Zhenyu WANG Xiaochao LIU Hu Jiang WANG Pengyuan QI Weizhi QIAO 《中国航空学报》2022,35(12):296-308
Load sensing pumps have been widely used in diverse hydraulic systems. Studies show that structural parameters have undeniable impacts on the characteristics and efficiency of the load sensing pump. The main purpose of this article is to study the influence of load sensing pump structure parameters on flow characteristics. In the present study, a nonlinear multi-parameter model is proposed for this type of pump. In this model, different parameters, including spool clearance,spool covering amount... 相似文献
134.
Safe soft landing of the lander is vital to the Mars surface exploration mission. Analysis and verification of the landing stability under uncertain terrain play an important role in lander design. However, the effect of uncertain terrain is ignored in most existing studies, making the analysis incomprehensive and increasing the risk of landing failure in practice. In this paper, a Mars lander with 10 attitude control thrusters is introduced and its dynamics model is then established considering... 相似文献
135.
A Reduced Order Model(ROM) based analysis method for turbomachinery cascade coupled mode flutter is presented in this paper. The unsteady aerodynamic model is established by a system identification technique combined with a set of Aerodynamic Influence Coefficients(AIC). Subsequently, the aerodynamic model is encoded into the state space and then coupled with the structural dynamic equations, resulting in a ROM of the cascade aeroelasticity. The cascade flutter can be determined by solving the e... 相似文献
136.
Effects of chemical energy accommodation on nonequilibrium flow and heat transfer to a catalytic wall 总被引:1,自引:1,他引:0
The accurate prediction of the aeroheating performance of hypersonic vehicles requires more detailed modeling of the catalysis process, rather than merely employing a catalytic coefficient. In this paper, the theoretical modeling, as well as the direct simulation Monte Carlo method,is used to preliminarily study the incomplete chemical energy accommodation effects, that is, only a part of the potential energy released in the heterogenous recombination reaction is transferred to the surface, whil... 相似文献
137.
迎风格式在二维非结构网格中的应用 总被引:2,自引:0,他引:2
将原来在结构网格中提出的AUSM+ (AdvectionUpstreamSplittingMethod)格式 ,推广应用于二维非结构网格中 .利用格林 高斯公式对控制体内的变量进行线性重构 ,获得空间二阶精度 ,并采用Barth型限制器以抑制数值解的振荡 .为提高计算效率 ,采用了自适应多重网格法 .最后给出了NACA0 0 1 2翼型和平板激波反射的几个Euler方程的算例 ,并进行了分析比较 . 相似文献
138.
The tracking control problem for Flexible Joint Manipulator Control System(FJMCS)with unmeasurable states is addressed in this paper. Firstly, a High-Gain Observer(HGO) is constructed to estimate the unmeasurable states and the uncertainties. Then, a Dynamic Surface Control(DSC) scheme is developed by using the estimation of HGO. The newly proposed controller has two advantages over the existing methods:(A) a novel Spike Suppression Function(SSF) is developed to avoid the estimation spike proble... 相似文献
139.
CHEN Zeyu CHEN Hongbin XU Jiyao L Daren ZHANG Shaodong XUE Xianghui TIAN Wenshou LIU Renqiang CHEN Wen HU Yongyun WANG Rui HU Dingzhu HU Xiong YANG Guotao GONG Yun LU Gaopeng 《空间科学学报》2018,38(5):763-780
In this paper we summarize the research results by Chinese scientists in 2016-2018. The focuses are placed on the researches of the middle and upper atmosphere, specifically the researches associated with groundbased observation capability development, dynamical processes, and properties of circulation and chemistryclimate coupling of the middle atmospheric layers. 相似文献
140.
This paper holds that the key to improve the hitting rate of air-to-air missiles is to decrease the error of initial alignment of the inertial navigation system. Therefore, considering that the alignment should be completed within a specified short time, this paper presents the theory of transfer alignment and the computing way of accuracy in an air-to-air missile, where the platform inertial navigation system, or master INS, is adopted on aircraft, and the strap-down inertial navigation system, or slave INS, is used on missile. It emphasizes the idea of transfer alignment, that is, calibration of the slave INS is based on the master platform, and adopts a reasoning measure to deal with the installing-error-angle. And it is proved by simulation that the transfer alignment can be quickly achieved. 相似文献