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421.
The dynamic modeling, finite-time trajectory tracking control and vibration suppression of a flexible two-link space robot are studied. Firstly, the dynamic model of the system is established by combining Lagrange method with assumed mode method. In order to ensure that the base attitude and the joints of space robot can reach the desired positions within a limited time, a non-singular fast terminal sliding mode (NFTSM) controller is designed, which realizes the finite-time convergence of the trajectory tracking errors. Subsequently, for the sake of suppressing the vibrations of flexible links, a hybrid tra-jectory based on the concept of the virtual control force is developed, which can reflect the flexible modes and the trajectory tracking errors simultaneously. By modifying the original control scheme, a NFTSM hybrid controller is proposed. The hybrid control scheme can not only realized attitude stabili-zation and trajectory tracking of joints in finite time, but also provide a new method of vibration sup-pression. The simulation results verify the effectiveness of the designed hybrid control strategy. 相似文献
422.
This paper focuses on the dynamic tracking control of ammunition manipulator system. A standard state space model for the ammunition manipulator electro-hydraulic system (AMEHS) with inherent non-linearities and uncertainties considered was established. To simultaneously suppress the violation of tracking error constraints and the complexity of differential explosion, a barrier Lyapunov functions-based dynamic surface control (BLF-DSC) method was proposed for the position tracking control of the ammunition manipulator. Theoretical analysis prove the stability of the closed-loop overall system and the tracking error converges to a prescribed neighborhood asymptotically. The effectiveness and dynamic tracking performance of the proposed control strategy is validated via simulation and experi-mental results. 相似文献
423.
The aerodynamic characteristics are vital for short cylindrical Terminal Sensitive Bullets(TSB)with low aspect ratio,especially in terminal trajectory.Currently,there is little research in terms of the TSB and short cylinder with two free ends,and particularly in this trajectory,where the scanning angle β and roll angle α vary over a broad range between 0° and 180°.In this work,wind tunnel experiments are first conducted to learn the effects of Reynolds number and scanning angle on aerodynamic parameters for short cylinder with aspect ratio L/D = 1.Similar to infinite cylinder,for the short cylinder with two free ends,the drag crisis phenomenon still exists in the critical regime 1.7 × 105 ≤ Re ≤ 6.8 × 105.Then 3D simulations are performed to demonstrate the aerodynamic characteristics of short cylinder and TSB over a broad range of Re,L/D,α and β.The sensitivity analysis of time step and grid are presented as well.When β=0°,for short cylinder,the drag crisis phenomenon was also observed in the simulation,but not as obvious as in the wind tunnel test.In some attitudes,there is an obvious Kármán vortex in the wake of short cylinder and TSB.The correlation between time-averaged aerodynamic coefficients and L/D,Re,α&β is discussed.The vortex shedding frequency and shear layer behavior are obtained for quasi-steady and unsteady flow.Finally,the effect of end's shape on drag reduction and vortex shedding frequency is analyzed. 相似文献
424.
美军是世界上唯一建立战争全域模拟仿真体系的军队,其建模与仿真建设高效管理的一些经验值得我军借鉴。本文归纳了美军建模与仿真管理5个方面的特点:高层机构统一领导,专职部门实施管理,以促进协作和共享为重点,规范化管理,模型、数据与服务一体化管理。并针对我军建模与仿真应用领域不广、协作共享不够、数据与服务管理欠缺的问题,提出了相应的建议。 相似文献
425.
426.
本文介绍了一个严格监督控制(Supervisorycontrol)定义下的局部自主机器人控制器GKD3的设计和实现,并从监督控制理论的角度,对GKD3的体系结构和功能进行了分析和讨论。 相似文献
427.
多媒体界面中的语音评价问题尚处于研究阶段。本文探讨了语音评价的基本方法,重点对语音的客观评价方法进行研究,提出了一种应用语音分析技术进行语音总体效能客观评价的计算机处理方法。 相似文献
428.
针对电子系统和设备设计的需要,本文提出一种面向产品对象的数据模型——设计体模型。阐述了产品数据的配置管理和版本管理的实施策略。 相似文献
429.
In modern warfare, many believe the decisive factor in winning a battle is seizing the right moment to shift from defense to attack, or vice versa. This paper attempts to bring that perspective to Lanchester's differential equations of warfare, and continues the application of Lanchester's linear law to the analysis of the World War II battle of Ardennes, as reported in earlier issues of Naval Research Logistics by Bracken and by Fricker. A new variable, shift time, accounting for the timing of the shift between defense and attack is explicitly included in our version of the model, and it helps obtain improved goodness of fit to historical data. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:653–661, 2001 相似文献
430.
基于AHP和模糊数学的课程评估系统初探 总被引:2,自引:0,他引:2
王晨 《中国人民武装警察部队学院学报》2001,17(5):56-58
给出课程评估的因素和指标体系,提出模糊数学与AHP相结合进行课程综合评价的原理与方法,使对问题的定性分析与定量分析得到有机结合,评估结果科学合理. 相似文献