针对星上微振动主动隔离/抑制的要求,以VCM(voice coil motor)作动器Stewart平台为控制装置,通过对其动力学模型解耦将控制转化为SISO(single input single output)问题;分析了Skyhook控制方法的隔振效果及其对抑振的局限性,在控制系统...针对星上微振动主动隔离/抑制的要求,以VCM(voice coil motor)作动器Stewart平台为控制装置,通过对其动力学模型解耦将控制转化为SISO(single input single output)问题;分析了Skyhook控制方法的隔振效果及其对抑振的局限性,在控制系统中加入了PFF(positive force feedback)控制回路,并引入加速度反馈环节以提高系统的鲁棒稳定性,形成一种振动主动隔离/抑制控制方法;利用Stewart平台的单杆开展了基础扫频激励和负载单频直接干扰共同作用下的S-DOF(single degree of freedom)微振动主动隔离/抑振控制实验,建立了Stewart平台刚/柔混合动力学模型并通过仿真研究了6-DOF振动主动隔离/抑振控制效果。实验和仿真结果表明:该方法可实现良好的振动主动隔离/抑制效果且性能稳定。展开更多
Bi0.85La0.15FeO3 thin film was prepared on ATO glass substrates by sol-gel technique. The effect of La doping on phase structure, film surface quality, ion valence, and ferroelectric/magnetic properties of Bio.85La0.1...Bi0.85La0.15FeO3 thin film was prepared on ATO glass substrates by sol-gel technique. The effect of La doping on phase structure, film surface quality, ion valence, and ferroelectric/magnetic properties of Bio.85La0.15FeO3 film were investigated. La doping suppressed the formation of impurity phases and the transition of Fe3＋ to Fe2＋ ions at room temperature. Compared with the un-doped BiFeO3, La-doping also increased the average grain size and the film density, which resulted in the decrease of film leakage current density. The remanent polarization and saturation magnetization were enhanced significantly by La doping. The remanent polariza- tion of Bi0.85La0.15FeO3 films gradually decreased while saturation magnetization increased with the decrease of measuring tempera- ture within a range from 50 to 300 K.展开更多
文摘针对星上微振动主动隔离/抑制的要求,以VCM(voice coil motor)作动器Stewart平台为控制装置,通过对其动力学模型解耦将控制转化为SISO(single input single output)问题;分析了Skyhook控制方法的隔振效果及其对抑振的局限性,在控制系统中加入了PFF(positive force feedback)控制回路,并引入加速度反馈环节以提高系统的鲁棒稳定性,形成一种振动主动隔离/抑制控制方法;利用Stewart平台的单杆开展了基础扫频激励和负载单频直接干扰共同作用下的S-DOF(single degree of freedom)微振动主动隔离/抑振控制实验,建立了Stewart平台刚/柔混合动力学模型并通过仿真研究了6-DOF振动主动隔离/抑振控制效果。实验和仿真结果表明:该方法可实现良好的振动主动隔离/抑制效果且性能稳定。
基金Project supported by National Natural Science Foundation of China(51072163,51001085)
文摘Bi0.85La0.15FeO3 thin film was prepared on ATO glass substrates by sol-gel technique. The effect of La doping on phase structure, film surface quality, ion valence, and ferroelectric/magnetic properties of Bio.85La0.15FeO3 film were investigated. La doping suppressed the formation of impurity phases and the transition of Fe3＋ to Fe2＋ ions at room temperature. Compared with the un-doped BiFeO3, La-doping also increased the average grain size and the film density, which resulted in the decrease of film leakage current density. The remanent polarization and saturation magnetization were enhanced significantly by La doping. The remanent polariza- tion of Bi0.85La0.15FeO3 films gradually decreased while saturation magnetization increased with the decrease of measuring tempera- ture within a range from 50 to 300 K.
