Dear Editor,This letter presents a class of saturated sliding mode control (SMC)strategy for linear systems subject to impulsive disturbance and input saturation. To ensure the feasibility of proposed SMC under satura...Dear Editor,This letter presents a class of saturated sliding mode control (SMC)strategy for linear systems subject to impulsive disturbance and input saturation. To ensure the feasibility of proposed SMC under saturation, a relationship is established among attraction domain, saturation structure and control gain.展开更多
A nmltichannel microwave interferometer system has been developed on the HL- 2A tokomak. Its working frequency is well designed to avoid the fringe jump effect. Taking the structure of HL-2A into account, its antennas...A nmltichannel microwave interferometer system has been developed on the HL- 2A tokomak. Its working frequency is well designed to avoid the fringe jump effect. Taking the structure of HL-2A into account, its antennas are installed in the horizontal direction, i.e. one launcher in high field side （HFS） and four receivers in low field side （LFS）. The fan-shaped measurement area covers those regions where the magnetohydrodynamics （MHD） instabilities are active. The heterodyne technique contributes to its high temporal resolution （1 μs）. It is possible for the multichannel system to realize simultaneous measurements of density and its fluctuation. The quadrature phase detection based on the zero-crossing method is introduced to density measureinent. With this system, reliable line-averaged densities and density profiles are obtained. The location of the saturated internal kink mode can be figured out from the mode showing different intensities on four channels, and the result agrees well with that measured by electron cyclotron emission imaging （ECEI）.展开更多
This paper presents an adaptive saturated integral sliding mode controller(ASISMC)integrated with an adaptive extended state observer(AESO)to address the challenges of nonlinear time-varying characteristics,parameter ...This paper presents an adaptive saturated integral sliding mode controller(ASISMC)integrated with an adaptive extended state observer(AESO)to address the challenges of nonlinear time-varying characteristics,parameter uncertainties,and external disturbances in valve positioner systems(VPS).To begin with,the VPS dynamic model is established by combining the valve positioner model,the control valve model,and the Euler-Lagrange model,where the uncertain parameters are estimated using the adaptive laws.Moreover,a tracking differentiator(TD)is implemented to ensure smooth and continuous signal processing.The AESO with structural self-regulation capability is also developed to estimate system perturbations and uncertainties effectively.Meanwhile,the proposed ASISMC is designed using adaptive laws based on the backstepping technique,further enhanced by setting saturation constraints on the integral sliding film surface.Finally,experimental validation confirms the superiority of the proposed approach over existing methods in improving control precision,response velocity,and disturbance rejection capability.展开更多
基金supported by the National Natural Science Foundation of China(62173215)the Major Basic Research Program of the Natural Science Foundation of Shandong Province in China(ZR2021ZD04,ZR2020ZD24)
文摘Dear Editor,This letter presents a class of saturated sliding mode control (SMC)strategy for linear systems subject to impulsive disturbance and input saturation. To ensure the feasibility of proposed SMC under saturation, a relationship is established among attraction domain, saturation structure and control gain.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB104002,2013GB107002,2014GB107001)National Natural Science Foundation of China(Nos.11475058,11475057,11261140326,11405049)
文摘A nmltichannel microwave interferometer system has been developed on the HL- 2A tokomak. Its working frequency is well designed to avoid the fringe jump effect. Taking the structure of HL-2A into account, its antennas are installed in the horizontal direction, i.e. one launcher in high field side （HFS） and four receivers in low field side （LFS）. The fan-shaped measurement area covers those regions where the magnetohydrodynamics （MHD） instabilities are active. The heterodyne technique contributes to its high temporal resolution （1 μs）. It is possible for the multichannel system to realize simultaneous measurements of density and its fluctuation. The quadrature phase detection based on the zero-crossing method is introduced to density measureinent. With this system, reliable line-averaged densities and density profiles are obtained. The location of the saturated internal kink mode can be figured out from the mode showing different intensities on four channels, and the result agrees well with that measured by electron cyclotron emission imaging （ECEI）.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0708902)the Ningbo Key Technology Research and Development Program(Grant No.2023Z018)+1 种基金the Liupanshan Laboratory Basic Research Program(Grant No.LPS-2024-KY-D-JC-0008)the Youth Fund of National Natural Science Foundation of China(Grant No.52205043)。
文摘This paper presents an adaptive saturated integral sliding mode controller(ASISMC)integrated with an adaptive extended state observer(AESO)to address the challenges of nonlinear time-varying characteristics,parameter uncertainties,and external disturbances in valve positioner systems(VPS).To begin with,the VPS dynamic model is established by combining the valve positioner model,the control valve model,and the Euler-Lagrange model,where the uncertain parameters are estimated using the adaptive laws.Moreover,a tracking differentiator(TD)is implemented to ensure smooth and continuous signal processing.The AESO with structural self-regulation capability is also developed to estimate system perturbations and uncertainties effectively.Meanwhile,the proposed ASISMC is designed using adaptive laws based on the backstepping technique,further enhanced by setting saturation constraints on the integral sliding film surface.Finally,experimental validation confirms the superiority of the proposed approach over existing methods in improving control precision,response velocity,and disturbance rejection capability.
