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891.
给出多阶段任务系统的分层次建模法.并举例在莱空间观测卫星可靠性分析上的应用,给出了上层模型和下层模型并对其任务可靠性进行了预计。 相似文献
892.
面向虚拟制造的车间集成规划技术研究 总被引:3,自引:0,他引:3
基于虚拟制造技术,提出了面向车间设计规划的虚拟制造系统体系结构,对其中涉及的车间模型进行了详细分析建模,并最终建立了车间集成设计规划系统。研究表明,该系统可以通过虚拟环境使车间设计规划更加直观,并可有效地协调车间从设计到实际运行各个阶段的关系,在实施方案前就达到系统最优化的目的。此外,该系统也为 RMS 的重组规划提供了技术支持。 相似文献
893.
排球球缝随机气动力辨识建模 总被引:5,自引:0,他引:5
本文应用H(Householder)变换求解病态法方程之最小二乘法及三次样条函数最小二乘法,对不同球缝随机性气动力模型进行辨识,提高了参数估计精度。讨论了不同球缝和各种发政治协商会议方式气动力的建模方法,给出了数学模型,并进行了验证,所得结果与实践经验一致。表明气动力模型较符合实际,建模方法可行,模型简单实用,为研究运用球缝发飘球技术,提供了重要的模型依据。 相似文献
894.
基于双循环的涡轮叶冠多学科设计优化 总被引:1,自引:0,他引:1
针对经典的多学科设计可行方法(MDF)的低效率问题,开展了利用可变复杂度建模方法改进MDF策略的研究.以涡轮叶冠为对象,综合考虑优化精度和优化效率,利用响应面方法近似高精度分析,简化计算难度,提高优化效率;合理引入可变复杂度建模方法,通过双循环结构优化策略周期性地调用高精度分析更新响应面方程来保证优化精度.基于双循环的涡轮叶冠多学科优化设计(MDO)表明,优化设计目标降低了1.4%,明显好于经典MDF策略(0.97%),整个优化策略共耗时2h39min,仅是经典MDF的优化时间的1/3. 相似文献
895.
896.
A novel reachable set(RS) model is developed within a framework of exoatmospheric interceptor engagement analysis. The boost phase steering scheme and trajectory distortion mechanism of the interceptor are firstly explored. A mathematical model of the distorted RS is then formulated through a dimension–reduction analysis. By treating the outer boundary of the RS on sphere surface as a spherical convex hull, two relevant theorems are proposed and the RS envelope is depicted by the computational geometry theory. Based on RS model, the algorithms of intercept window analysis and launch parameters determination are proposed, and numerical simulations are carried out for interceptors with different energy or launch points. Results show that the proposed method can avoid intensive on-line computation and provide an accurate and effective approach for interceptor engagement analysis. The suggested RS model also serves as a ready reference to other related problems such as interceptor effectiveness evaluation and platform disposition. 相似文献
897.
Dynamic modeling of a hose-drogue aerial refueling system(HDARS) and an integral sliding mode backstepping controller design for the hose whipping phenomenon(HWP) during probe-drogue coupling are studied. Firstly, a dynamic model of the variable-length hose-drogue assembly is built for the sake of exploiting suppression methods for the whipping phenomenon.Based on the lumped parameter method, the hose is modeled by a series of variable-length links connected with frictionless joints. A set of iterative equations of the hose's three-dimensional motion is derived subject to hose reeling in/out, tanker motion, gravity, and aerodynamic loads accounting for the effects of steady wind, atmospheric turbulence, and tanker wake. Secondly,relying on a permanent magnet synchronous motor and high-precision position sensors, a new active control strategy for the HWP on the basis of the relative position between the tanker and the receiver is proposed. Considering the strict-feedback configuration of the permanent magnet synchronous motor, a rotor position control law based on the backstepping method is designed to insure global stability. An integral of the rotor position error and an exponential sliding mode reaching law of the current errors are applied to enhance control accuracy and robustness. Finally,the simulation results show the effectiveness of the proposed model and control laws. 相似文献
898.
动态空域配置旨在通过对各类型空域功能块的设计、构架、配置和使用,实现空域的动态配置功能,使管制空域灵活地匹配空中交通实际变化的需求。在此概念下建立了以最小运营成本为目标的航路调整规划模型,在模型中考虑某些航路段可以动态地开关-闭合,引入动态航路的开放成本和使用成本,以最短开放时间、最大管制负荷和航路复杂度、安全性为约束条件,采取改进的遗传算法进行求解,验证了模型的正确性和可行性。计算结果表明:用模型制定的优化策略,充分利用了空域资源,减少了延误损失,总的航班运营成本减少了15%。 相似文献
899.
To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle- tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP (rotation tool center point control) and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software struc- ture, the instructions with respect to the cutter's position and orientation can be directly carried out in the CNC system. 相似文献