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振频法索力监测中自振频率的频谱倍增方法 被引量:5
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作者 刘琳 陈伟民 +2 位作者 章鹏 胡顺仁 罗伟 《仪器仪表学报》 EI CAS CSCD 北大核心 2011年第11期2443-2448,共6页
利用振频法对索力进行长期在线监测时,为高效准确地自动识别拉索的自振频率,就必须避免拉索随机振动信号的非平稳性和频谱微弱等不利条件,减小随机噪声及干扰。根据斜拉索振型的特征,提出频谱倍增法:对单组振动信号频谱幅值进行m次数组... 利用振频法对索力进行长期在线监测时,为高效准确地自动识别拉索的自振频率,就必须避免拉索随机振动信号的非平稳性和频谱微弱等不利条件,减小随机噪声及干扰。根据斜拉索振型的特征,提出频谱倍增法:对单组振动信号频谱幅值进行m次数组乘积,或者对m组相邻频谱幅值进行一次数组乘积;并通过理论分析证明了该方法能够将信噪比至少提高m倍,是常规累加平均法的槡m倍。以重庆马桑溪长江大桥斜拉索为研究对象进行现场对比试验,分别采用频谱倍增法和累加平均法进行自振频率的自动识别,倍增法基频识别结果误差减少至4%以内,且识别效率提高了5~10倍。试验结果表明:倍增法不仅提高了识别结果的精度,还缩短了识别所需的时间,提高了识别效率。 展开更多
关键词 索力监测 振频法 随机激励 谱倍增 信噪比
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振频法索力测量系统中数据采样参数匹配研究
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作者 刘琳 陈伟民 +1 位作者 章鹏 胡顺仁 《传感器与微系统》 CSCD 北大核心 2011年第2期23-25,28,共4页
利用振频法进行索力测量,数据采样参数设置不当会大大降低基频识别精度进而降低索力测量精度。在分析采样参数即采样率和采样数对基频识别精度影响的基础上,根据奈奎斯特定律,兼顾测量实时性和有限的数据存储空间,提出最优化数据采样参... 利用振频法进行索力测量,数据采样参数设置不当会大大降低基频识别精度进而降低索力测量精度。在分析采样参数即采样率和采样数对基频识别精度影响的基础上,根据奈奎斯特定律,兼顾测量实时性和有限的数据存储空间,提出最优化数据采样参数匹配方法,以提高测量精度。对马桑溪长江大桥斜拉索索力进行现场测试,结果表明:按照最优的参数匹配方法进行合理的参数设置,索力测量精度至少提高2倍,具有较好的工程应用价值。 展开更多
关键词 振频法 索力测量 采样参数 精度 分辨力
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Method for optimizing manipulator's geometrical parameters and selecting reducers 被引量:4
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作者 杜志江 肖永强 董为 《Journal of Central South University》 SCIE EI CAS 2013年第5期1235-1244,共10页
A geometrical parameters optimization and reducers selection method was proposed for robotic manipulators design. The Lagrangian approach was employed in deriving the dynamic model of a two-DOF manipulator. The flexib... A geometrical parameters optimization and reducers selection method was proposed for robotic manipulators design. The Lagrangian approach was employed in deriving the dynamic model of a two-DOF manipulator. The flexibility of links and joints was taken into account in the mechanical structure dimensions optimization and reducers selection, in which Timoshenko model was used to discretize the hollow links. Two criteria, i.e. maximization of fundamental frequency and minimization of self-mass/load ratio, were utilized to optimize the manipulators. The NSGA-II (fast elitist nondominated sorting genetic algorithms) was employed to solve the multi-objective optimization problem. How the joints flexibility affects the manipulators design was analyzed and shown in the numerical analysis example. The results indicate that simultaneous consideration of the joints and the links flexibility is very necessary for manipulators optimal design. Finally, several optimal combinations were provided. The effectiveness of the optimization method was proved by comparing with ADAMS simulation results. The self-mass/load ratio error of the two methods is within 10%. The maximum error of the natural frequency by the two methods is 23.74%. The method proposed in this work provides a fast and effective pathway for manipulator design and reducers selection. 展开更多
关键词 robotic manipulator optimal design reducer selection flexible links flexible joints
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