In order to explore the precise dynamic response of the maglev train and verify the validity of proposed controller,a maglev guideway-electromagnet-air spring-cabin coupled model is developed in the first step.Based o...In order to explore the precise dynamic response of the maglev train and verify the validity of proposed controller,a maglev guideway-electromagnet-air spring-cabin coupled model is developed in the first step.Based on the coupled model,the stresses of the modules are analyzed,and it is pointed out that the inherent nonlinearity,the inner coupling,misalignments between the sensors and actuators,and external disturbances are the main issues that should be considered for the maglev engineering.Furthermore,a feedback linearization controller based on the mathematical model of a maglev module is derived,in which the nonlinearity,coupling and misalignments are taken into account.Then,to attenuate the effect of external disturbances,a disturbance observer is proposed and the dynamics of the estimation error is analyzed using the input-to-state stability theory.It shows that the error is negligible under a low-frequency disturbance.However,at the high-frequency range,the error is unacceptable and the disturbances can not be compensated in time,which lead to over designed fluctuations of levitation gap,even a clash between the upper surface of electromagnet and lower surface of guideway.To solve this problem,a novel nonlinear acceleration feedback is put forward to enhancing the attenuation ability of fast varying disturbances.Finally,numerical comparisons show that the proposed controller outperforms the traditional feedback linearization controller and maintains good robustness under disturbances.展开更多
The linear stability analysis of the fiber suspension Taylor-Couette flow against axisymmetric and non-axisymmetric disturbances is investigated. A generalized complex eigenvalue problem generated from the linearized ...The linear stability analysis of the fiber suspension Taylor-Couette flow against axisymmetric and non-axisymmetric disturbances is investigated. A generalized complex eigenvalue problem generated from the linearized set of the three-dimensional governing system equations around the basic Couette azimuthal solution are solved numerically with the Chebyshev spectral method. In a wide range of radius ratios and the magnitudes of counter rotating, critical bifurcation thresholds from the axisymmetric Couette flow to the flow with different azimuthal wave numbers are obtained. The complex dispersion relations of the linearized stability equation system for vortex patterns with different azimuthal wave number are calculated for real axial wave numbers for axially extended vortex structures.展开更多
基金Project(60404003)supported by the National Natural Science Foundation of China
文摘In order to explore the precise dynamic response of the maglev train and verify the validity of proposed controller,a maglev guideway-electromagnet-air spring-cabin coupled model is developed in the first step.Based on the coupled model,the stresses of the modules are analyzed,and it is pointed out that the inherent nonlinearity,the inner coupling,misalignments between the sensors and actuators,and external disturbances are the main issues that should be considered for the maglev engineering.Furthermore,a feedback linearization controller based on the mathematical model of a maglev module is derived,in which the nonlinearity,coupling and misalignments are taken into account.Then,to attenuate the effect of external disturbances,a disturbance observer is proposed and the dynamics of the estimation error is analyzed using the input-to-state stability theory.It shows that the error is negligible under a low-frequency disturbance.However,at the high-frequency range,the error is unacceptable and the disturbances can not be compensated in time,which lead to over designed fluctuations of levitation gap,even a clash between the upper surface of electromagnet and lower surface of guideway.To solve this problem,a novel nonlinear acceleration feedback is put forward to enhancing the attenuation ability of fast varying disturbances.Finally,numerical comparisons show that the proposed controller outperforms the traditional feedback linearization controller and maintains good robustness under disturbances.
基金the Major Programof the National Natural Science Foundation of China with Grant No10632070
文摘The linear stability analysis of the fiber suspension Taylor-Couette flow against axisymmetric and non-axisymmetric disturbances is investigated. A generalized complex eigenvalue problem generated from the linearized set of the three-dimensional governing system equations around the basic Couette azimuthal solution are solved numerically with the Chebyshev spectral method. In a wide range of radius ratios and the magnitudes of counter rotating, critical bifurcation thresholds from the axisymmetric Couette flow to the flow with different azimuthal wave numbers are obtained. The complex dispersion relations of the linearized stability equation system for vortex patterns with different azimuthal wave number are calculated for real axial wave numbers for axially extended vortex structures.
