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171.
Pendulum tuned mass damper (PTMD) is usually used to control the horizontal vibration of a tall building. However, traditional PTMD is highly sensitive to frequency deviation and difficult to adjust its frequency. In order to improve this problem of traditional PTMD and protect a tall building more effectively, a novel PTMD, called self‐adjustable variable pendulum tuned mass damper (SAVP‐TMD), is proposed in this paper. On the basis of the acceleration ratio between TMD and primary structure, the SAVP‐TMD can retune itself by varying the length of the pendulum according to the improved acceleration ratio‐based adjustment algorithm. PTMD and primary structural accelerations are obtained from two accelerometers respectively, and the acceleration ratio is calculated in a microcontroller, then, the stepper motor will adjust the pendulum under the guidance of the microcontroller under a specific harmonic excitation. The improved acceleration ratio‐based adjustment algorithm is proposed and compared to solve the nonconvergent retuning problem. The SAVP‐TMD can be regarded as a passive damper including a frequency adjustment device. A single‐degree‐of‐freedom structure model is used to verify the effectiveness of SAVP‐TMD through both experimental study and numerical simulation. In order to further verify the effect of SAVP‐TMD in the MDOF structure, a five‐storey structure coupled with an SAVP‐TMD is proposed as a case study. The results of experiment, simulation, and case study all show that SAVP‐TMD can retune itself to the primary structural dominant frequency robustly, and the retuned PTMD has a better vibration control effect than the mistuned one. 相似文献
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为克服传统光电被动测距系统稳定性差、远距离条件下测距精度收敛性差、系统难以小型化等不足,本文提出一种基于目标特征尺寸的可视化光电被动测距系统。建立了被动测距模型并分析测距原理,从理论上分析获得距离反演公式和测距误差精度;设计了被动测距算法并分析相关成像参数获取途径和方法;通过高清成像器、半导体激光器和信号处理器等软硬件设计,实现了系统的可视化被动测距功能和全天候图像信息获取;最后通过目标特征尺寸及其成像系统参数反演目标距离,实现了在成像过程中实时测距并进行被动测距实验验证。实验结果表明,被动测距精度优于10%,当前软硬件参数配置下,目标的测距距离大于1km,测距鲁棒性好,性能稳定,可广泛应用于全天候目标图像信息获取和光电被动测距的实际工程实践中。 相似文献
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In this article we present two contributions to the study of coaxial waveguide structures. First, we present an efficient and accurate technique to evaluate the modes in the coaxial waveguides; second, we analyze junctions involving coaxial and circular waveguides using the multimode equivalent network representation. Numerical and experimental results are presented, showing good agreement. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 180–194, 1997. 相似文献
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Presents the principles of the passive robot system for measuring spacesuit joint mobility. The model of passive robot is developed. Based on its special mechanical structure, the model of the flexible IVA (intravehicular activity) spacesuit' s arm according to robotics is built. The inverse kinematics of a spacesuit' s arm based on artificial neural networks is put forward. Also, the self-learning algorithm of the network architecture based on generalization ability is developed, which ensures that the network architecture is designed and optimized. The joint mobility of an actual IVA spacesuit is measured. Experimental results prove that the theoretical system is correct and available, and the measuring system has high preciseness. 相似文献