Since we find out that the global spectral model with trapezoidal truncation has higher resolution in high latitudes(polar cap)than in low latitudes,this paper presents a global spectral model with variable poles whic...Since we find out that the global spectral model with trapezoidal truncation has higher resolution in high latitudes(polar cap)than in low latitudes,this paper presents a global spectral model with variable poles which can be located at the center of interested area.The transform methods from traditional global spectral model to the new model are given and applied to a shallow-water equation model.The control ex- periments for 72h predictions were carried out.The“northern pole”in the transformed model was located at 15°N,135°E.And the results showed that the predictions of weather systems in the area around the“new pole”(the polar cap,latitudes >60°)were better than those by the traditional model and the root mean square errors were improved.展开更多
The variable structure control （VSC） theory is applied to the electro-hydraulic servo system here. The VSC control law is achieved using Lyapunov method and pole placement. To eliminate the chattering phenomena, a s...The variable structure control （VSC） theory is applied to the electro-hydraulic servo system here. The VSC control law is achieved using Lyapunov method and pole placement. To eliminate the chattering phenomena, a saturation function is adopted. The proposed VSC approach is fairly robust to load disturbance and system parameter variation. Since the distortion. including phase lag and amplitude attenuation occurs in the system sinusoid response, the amplitude and phase control （APC） algorithm, based on Adaline neural network and using LMS algorithm, is developed for distortion cancellation. The APC controller is simple and can on-line adjust, thus it gives accurate tracking.展开更多
文摘Since we find out that the global spectral model with trapezoidal truncation has higher resolution in high latitudes(polar cap)than in low latitudes,this paper presents a global spectral model with variable poles which can be located at the center of interested area.The transform methods from traditional global spectral model to the new model are given and applied to a shallow-water equation model.The control ex- periments for 72h predictions were carried out.The“northern pole”in the transformed model was located at 15°N,135°E.And the results showed that the predictions of weather systems in the area around the“new pole”(the polar cap,latitudes >60°)were better than those by the traditional model and the root mean square errors were improved.
文摘The variable structure control （VSC） theory is applied to the electro-hydraulic servo system here. The VSC control law is achieved using Lyapunov method and pole placement. To eliminate the chattering phenomena, a saturation function is adopted. The proposed VSC approach is fairly robust to load disturbance and system parameter variation. Since the distortion. including phase lag and amplitude attenuation occurs in the system sinusoid response, the amplitude and phase control （APC） algorithm, based on Adaline neural network and using LMS algorithm, is developed for distortion cancellation. The APC controller is simple and can on-line adjust, thus it gives accurate tracking.
