共查询到20条相似文献,搜索用时 15 毫秒
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The variable structure control (VSC) and the stabilizer design by using pole placement technique are applied to the tracking control of the flexible slider-crank mechanism under impact. The VSC strategy is employed to track the crank angular position and speed, while the stabilizer design is involved to suppress the flexible vibrations simultaneously. From the theoretical impact consideration, three approaches including the generalized momentum balance (GMB), the continuous force model (CFM), and the CFM associated with the effective mass compensation EMC are adopted, and are derived on the basis of the energy and impulse-momentum conservations. Simulation results are provided to demonstrate the performance of the motor-controller flexible slider-crank mechanism not only accomplishing good tracking trajectory of the crank angle, but also eliminating vibrations of the flexible connecting rod. 相似文献
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ACTIVE CONTROL EXPERIMENTS FOR ACOUSTIC RADIATION REDUCTION OF A SANDWICH PANEL: FEEDBACK AND FEEDFORWARD INVESTIGATIONS 总被引:1,自引:0,他引:1
Experiments were conducted on a square panel of a honeycomb sandwich material, to compare and evaluate various active control strategies for acoustic radiation reduction. The panel was clamped between two soundproofed rooms, the receiving room being equipped with a moving system and a microphone. This paper compares different sensor/actuator arrangements. The two basic configurations are 8 PVDF patches used as sensors on one side of the panel and 8 PZT patches on the other side, versus several accelerometers or microphones as sensors and secondary shakers as actuators. In all cases, the primary excitation is provided by a shaker generating either pure tones or broadband noise on wide frequency bands (0-800 Hz). The second comparison level is relative to the control approaches: LMS feedforward and collocated feedback control strategies are investigated for broadband primary excitations. One of the most interesting aspects of the problem is to evaluate active control methods applied to a highly damped material. In particular, modal analysis and system identification are much more difficult than when applied to lightly damped metallic structures, due to the high modal overlap. 相似文献
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The nonlinear effects of large amplitude ion acoustic wave are studied theoretically and experimentally, so as to obtain the amplitude threshold for producing the nonlinear effects, the half width of the trapped region and the transitional region width caused by collisions. The experimental results are in good agreement with the theoretical predictions. 相似文献
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A.S. AL-DMOURK.S. MOHAMMAD 《Journal of sound and vibration》2002,253(3):545-569
Principal component analysis is used to simplify the extraction of the natural frequencies and their corresponding orthonormal mode shapes directly from experimental data of unknown flexible structures. A control law is designed using a state-space modal model and is tested on different structures. The results are extremely encouraging and demonstrate successful implementation of the active control strategies. The controller actuator as well as the detection sensor locations are examined throughout the structure length. 相似文献
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本文用激光器模式耦合半经典理论,阐述激光腔内吸收光谱学方法的物理机制,探求影响灵敏度的因素。
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通过对第一过渡族自由离子光谱参数实验值的线性分析和计算,得到了具有系统性和规律性的最优化3d电子径向波函数。并用最优化3d电子径向波函数计算了自由离子光谱,理论计算与实验进行了比较。 相似文献
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扼要地阐述了X射线、电子束辐照材料时所产生的热激波与高速碰撞、炸药爆炸所产生的压缩波之间一些不同的现象特征,可为热激波的分析、研究以及模拟提供参考。 相似文献
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A SYSTEMATIC DISTORTED WAVE IMPULSE APPROXIMATION ANALYSIS OF THE CONVENTIONAL MECHANISM FOR PION DOUBLE CHARGE EXCHANGE 下载免费PDF全文
In the framework of the distorted wave impulse approximation,a systematic analysis is performed for the contribution from the conventional mechanism to the double charge exchange to the double isobaric analog state.The effects of distortions of pions,nuclear wave functions,short-range correlation functions,parameters of form factors,the spin-dependent term in the πN amblitude etc.are examined.It is shown that all these elements are very important and not negligible for the conventional mechanism.But after including the effects of all these elements,the conventional mechanism is still not able to reproduce the experimental excitation function and agular distribution for the energy region of 0—300MeV,therefore the effects of some other mechanisms should be included. 相似文献
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磁体结构的好坏将直接关系到磁体的制造成本以及磁体能否正常运行.在磁体结构的优化设计中,选定磁体的体积为目标函数,在满足磁体储能,符合超导材料的B~J特性,尽量减小漏磁等条件下,使目标函数达到最小.文章选定新一带超导涂层导体Ⅵ瑚为SMES线圈的制造材料,分析了Y系带材的材料特性,并采用大型有限元仿真软件ANSYS和磁体优化中常用的算法-模拟退火算法(simulated annealing)对SMES线圈进行优化仿真分析.得出最优的磁体结构. 相似文献
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In terms of Newton two-state model, by choosing two sets of generalized co-ordinates, this paper develops a unified dynamic model between the separation and collision process for the elastic linkage mechanism. This model incorporates the effects of rigidity and elasticity coupling and the angular velocity of crank is assumed to be variable in the operation. In addition, this paper provides a more simple and practical numerical solution method for convenient analysis. Through an example, the dynamic responses of the elastic linkage mechanism with clearances are analyzed, both the effects of elasticity and clearance on the dynamic behaviors of the mechanism are analyzed simultaneously and the non-linear behaviors caused by the clearance joints are analyzed by the dynamic model of rigid mechanism. 相似文献
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本文为解决非线性微分方程自治系统的周期轨道的数值计算,提出了一种最优控制的数值计算方法。其方法的实质是利用连续的打靶法,在非线性最小二乘公式的监护下,附加惩罚函数进行控制来实现的。并利用该法计算了典型的化学反应模型。 相似文献
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本文给出了高温等离子体中高频波激发低频磁场和离子声波强湍动过程的重整化理论,以便改善通常的弱非线性处理方法,从Vlasov-Maxwell方程组出发,在Fourier表象中得到了包含“最发散”和“次发散”效应互相耦合的高频和低频传播于重整化方程组,从而获得了高、低频振荡粒子重整化分布函数和场的耦合关系。在“最发散”重整化近似下,我们求解了高低频传播子方程组,得到了展开到v4(高频湍动场能密度与等离子体热能密度之比)一次方的近似解和重整化介电函数等表达式。然后,在Fourier逆变换下导得了我们所要的时空表用中重整化强湍动方程组。最后,作为一个说明重整化作用的例子,在一维稳态下求解了孤立子的形式。
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