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Arc-tangent Transformation Algorithm for Active Impulsive Noise Control

SHAO Jun;ZHOU Ya-li;ZHANG Qi-zhi

2012, 32 (2): 27-31. DOI: 103969/j.issn.1006-1355-2012.02.006

Abstract （1296）

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In recent years, some effective algorithms for active impulsive noise control have been proposed. But these algorithms may not be stable due to the high-and-sharp peaks of the impulsive noise. To overcome the shortage of these algorithms, a new algorithm based on minimizing the squared arc-tangent transformation of the error signal was proposed. This algorithm doesn’t need to consider thresholds estimation and parameters selection based on priori knowledge of impulsive noise. Moreover, the algorithm is simple in structure, and easy to be realized. The simulation results show that the proposed algorithm can effectively eliminate the impulsive noise, and compared with the other algorithms, the performance of the proposed algorithm has a better convergence and stability.

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Modal Analysis and Model Updating of Optical Element

SHAO Jun;YE Jing-feng;HU Zhi-yun;ZHANG Zhen-rong;HUANG Mei-sheng

2012, 32 (1): 39-42. DOI: 10.3969/j.issn.1006-1355-2012.01.009

Abstract （1485）

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To study the dynamic performance of optical elements, the modal experiment for an optical mirror mount was carried out as an example. Its dynamic computation model was established and its reliability was verified. And the modal analysis was done. To reduce the deviation between the theoretical model and practical situation, the dynamic computation model was updated from time to time by analyzing the relative sensitivity of the frequency to the model parameters such as material property, Poisson ratio, elastic modulus, geometrical dimensions and so on. Then the most sensitive parameter was found, and the model was updated according to this parameter. It is found that the dynamic characteristics of the updated model is closer to the measurement data, and the frequency deviation between the simulation and measurement is obviously reduced. Results show that the dynamic computation model is capable for describing the dynamic characteristics of the optical elements.

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Modal Test and Vibration Analysis of the Optical Element with Different Boundary Constraint Conditions

SHAO Jun;YE Jing-feng;HU Zhi-yun;ZHANG Zhen-rong

2011, 31 (6): 165-168. DOI: 10.3969/j.issn.1006-1355-2011.06.037

Abstract （1500）

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To analyze and evaluate anti-vibration performance of the optical element, a series of modal experiments about the L-shaped pad element with different boundary constraint conditions is carried on. Firstly, the deviation of the results from ANSYS simulation and measurement is limited in an allowable range, so that the definition of modal performance and the reliability of experiments of the model are validated. Secondly, anti-vibration performance of optical element is analyzed based on the experiments data, and the modal parameters of the element with different boundary conditions are obtained. Finally, the working stability of the element with different assembly situation is analyzed according to the different dynamic characteristics under different boundary constraint conditions. This work may provide a reference for improving the anti-vibration and working performances of optical elements in different environments.