The torsional vibration of power transmission shaft is a phenomenon whose analytical modeling can be represented by a differential equation of motion proposed by technical literature. The solutions of these equations ...The torsional vibration of power transmission shaft is a phenomenon whose analytical modeling can be represented by a differential equation of motion proposed by technical literature. The solutions of these equations need coefficients and parameters that, usually, must be experimentally estimated. This work uses a resistive electric SG （strain gage） to dynamically determine strains produced in the shaft due to harmonic oscillatory motion under multiaxial loading. This movement is simulated on a prototype specially developed for this purpose. It comprises a pulley attached to the end of a stepped cantilevered shaft, which is clamped at the opposite end. In this configuration, a cam generates a torque to the system, springs regulate the stiffness and the damping coefficient of the assembly, as well as they can be suitably adjusted to produce an underdamped condition. The main advantage, highlighted in this study, refers to a major simplification. Although the system under study shows multiple degrees of freedom （torsion and bending）, the shape and the positioning of linking SGs with the resistor bridge （Wheatstone Bridge）, allow ＂to evaluate the loading effects independently, as if only one degree of freedom of the system exists at a time domain. Strains graphs for two forms of cyclic torsional oscillation, analytical and experimental, were successfully generated.展开更多
FY-4 is the second generation of Chinese geostationary satellite for quantitative remote sensing meteorological application. The detection efficiency, spectral bands, spatial and time resolution have been greatly impr...FY-4 is the second generation of Chinese geostationary satellite for quantitative remote sensing meteorological application. The detection efficiency, spectral bands, spatial and time resolution have been greatly improved with respect to those of first generation, as well as the radiometric calibration and sensitivity. The combination of multichannel detection and vertical sounding was first realized on FY-4, because both the Advanced Geostationary Radiation Imager(AGRI) and Geostationary Interferometric Infrared Sounder(GIIRS) are on the same spacecraft. The main performance of the payloads including AGRI, GIIRS and Lightning Mapping Imager, and the spacecraft bus are presented, the performance being equivalent to the level of the third generation meteorological satellites in Europe and USA. The acquiring methods of remote sensing data including multichannel and high precision quantitative observing, imaging collection of the ground and cloud, vertical observation of atmospheric temperature and moisture, lightning imaging observation and space environment detection are shown. Several innovative technologies including high accuracy rotation angle detection and scanning control, high precision calibration, micro vibration suppression, unified reference of platform and payload and on-orbit measurement, real-time image navigation and registration on-orbit were applied in FY-4.展开更多
文摘The torsional vibration of power transmission shaft is a phenomenon whose analytical modeling can be represented by a differential equation of motion proposed by technical literature. The solutions of these equations need coefficients and parameters that, usually, must be experimentally estimated. This work uses a resistive electric SG （strain gage） to dynamically determine strains produced in the shaft due to harmonic oscillatory motion under multiaxial loading. This movement is simulated on a prototype specially developed for this purpose. It comprises a pulley attached to the end of a stepped cantilevered shaft, which is clamped at the opposite end. In this configuration, a cam generates a torque to the system, springs regulate the stiffness and the damping coefficient of the assembly, as well as they can be suitably adjusted to produce an underdamped condition. The main advantage, highlighted in this study, refers to a major simplification. Although the system under study shows multiple degrees of freedom （torsion and bending）, the shape and the positioning of linking SGs with the resistor bridge （Wheatstone Bridge）, allow ＂to evaluate the loading effects independently, as if only one degree of freedom of the system exists at a time domain. Strains graphs for two forms of cyclic torsional oscillation, analytical and experimental, were successfully generated.
文摘FY-4 is the second generation of Chinese geostationary satellite for quantitative remote sensing meteorological application. The detection efficiency, spectral bands, spatial and time resolution have been greatly improved with respect to those of first generation, as well as the radiometric calibration and sensitivity. The combination of multichannel detection and vertical sounding was first realized on FY-4, because both the Advanced Geostationary Radiation Imager(AGRI) and Geostationary Interferometric Infrared Sounder(GIIRS) are on the same spacecraft. The main performance of the payloads including AGRI, GIIRS and Lightning Mapping Imager, and the spacecraft bus are presented, the performance being equivalent to the level of the third generation meteorological satellites in Europe and USA. The acquiring methods of remote sensing data including multichannel and high precision quantitative observing, imaging collection of the ground and cloud, vertical observation of atmospheric temperature and moisture, lightning imaging observation and space environment detection are shown. Several innovative technologies including high accuracy rotation angle detection and scanning control, high precision calibration, micro vibration suppression, unified reference of platform and payload and on-orbit measurement, real-time image navigation and registration on-orbit were applied in FY-4.
