A neural-network-based adaptive gain scheduling backstepping sliding mode control（NNAGS-BSMC） approach for a class of uncertain strict-feedback nonlinear system is proposed.First, the control problem of uncertain st...A neural-network-based adaptive gain scheduling backstepping sliding mode control（NNAGS-BSMC） approach for a class of uncertain strict-feedback nonlinear system is proposed.First, the control problem of uncertain strict-feedback nonlinear systems is formulated. Second, the detailed design of NNAGSBSMC is described. The sliding mode control（SMC） law is designed to track a referenced output via backstepping technique.To decrease chattering result from SMC, a radial basis function neural network（RBFNN） is employed to construct the NNAGSBSMC to facilitate adaptive gain scheduling, in which the gains are scheduled adaptively via neural network（NN）, with sliding surface and its differential as NN inputs and the gains as NN outputs. Finally, the verification example is given to show the effectiveness and robustness of the proposed approach. Contrasting simulation results indicate that the NNAGS-BSMC decreases the chattering effectively and has better control performance against the BSMC.展开更多
基于模块化多电平换流器的静止同步补偿器(stationary synchronous compensator based on modular multilevel converters,MMC-STATCOM)是高压电力系统中无功补偿的关键设备,其传统线性控制器性能会因运行点的大范围变化而恶化。针对该...基于模块化多电平换流器的静止同步补偿器(stationary synchronous compensator based on modular multilevel converters,MMC-STATCOM)是高压电力系统中无功补偿的关键设备,其传统线性控制器性能会因运行点的大范围变化而恶化。针对该问题,该文提出了一种基于滑模状态反馈精确线性化的非线性智能控制策略,首先通过选择合适的输出函数、坐标变换,将不做任何简化的3阶MMC-STATCOM非线性模型转化为一个可控的Brunovsky标准型线性系统,并通过数学理论证明了该模型满足精确线性化条件。然后采用改进的粒子群算法配置其反馈增益矩阵,利用积分滑模控制计算其平衡点。最后通过状态反馈使各个状态变量快速收敛至平衡点。将该控制策略与传统PI控制、LQR状态反馈控制通过硬件在环实时仿真平台进行对比实验,结果表明该控制策略具有更好的动态特性、暂态稳定性、鲁棒性,尤其适用于运行环境发生大扰动时。此外,该控制策略的设计过程可以拓展应用于其他类型的柔性交流输电装置。展开更多
The principle of laser optical feedback microscope was presented and demonstrated. Three methods to advance the vertical resolution of laser optical feedback microscope were experimentally studied. The first one is to...The principle of laser optical feedback microscope was presented and demonstrated. Three methods to advance the vertical resolution of laser optical feedback microscope were experimentally studied. The first one is to detect the two polarized lights’ intensities separately with a Wollaston prism instead of to detect the whole light’s intensity. The second is that both of the two orthogonally polarized lights of a birefringent dual frequency laser are fed back. The third one is that only one of the orthogonally polarized lights is fed back. The experimental results show that the modes competition between orthogonally polarized lights can be used to improve the vertical resolution of laser optical feedback microscope effectively.展开更多
A decoupled nonsingular terminal sliding mode control（DNTSMC） approach is proposed to address the tracking control problem of affine nonlinear systems.A nonsingular terminal sliding mode control（NTSMC） method is p...A decoupled nonsingular terminal sliding mode control（DNTSMC） approach is proposed to address the tracking control problem of affine nonlinear systems.A nonsingular terminal sliding mode control（NTSMC） method is presented,in which the nonsingular terminal sliding surface is defined as a special nonsingular terminal function and the convergence time of the system states can be specified.The affine nonlinear system is firstly decoupled into linear subsystems via feedback linearization.Then,a nonsingular terminal sliding surface is defined and the NTSMC method is applied to each subsystem separately to ensure the finite time convergence of the closed-loop system.The verification example is given to demonstrate the effectiveness and robustness of the proposed approach.The proposed approach exhibits a considerable advantage in terms of faster tracking error convergence and less chattering compared with the conventional sliding mode control（CSMC）.展开更多
基金supported by the National Natural Science Foundation of China(11502288)the Natural Science Foundation of Hunan Province(2016JJ3019)+1 种基金the Aeronautical Science Foundation of China(2017ZA88001)the Scientific Research Project of National University of Defense Technology(ZK17-03-32)
文摘A neural-network-based adaptive gain scheduling backstepping sliding mode control（NNAGS-BSMC） approach for a class of uncertain strict-feedback nonlinear system is proposed.First, the control problem of uncertain strict-feedback nonlinear systems is formulated. Second, the detailed design of NNAGSBSMC is described. The sliding mode control（SMC） law is designed to track a referenced output via backstepping technique.To decrease chattering result from SMC, a radial basis function neural network（RBFNN） is employed to construct the NNAGSBSMC to facilitate adaptive gain scheduling, in which the gains are scheduled adaptively via neural network（NN）, with sliding surface and its differential as NN inputs and the gains as NN outputs. Finally, the verification example is given to show the effectiveness and robustness of the proposed approach. Contrasting simulation results indicate that the NNAGS-BSMC decreases the chattering effectively and has better control performance against the BSMC.
文摘基于模块化多电平换流器的静止同步补偿器(stationary synchronous compensator based on modular multilevel converters,MMC-STATCOM)是高压电力系统中无功补偿的关键设备,其传统线性控制器性能会因运行点的大范围变化而恶化。针对该问题,该文提出了一种基于滑模状态反馈精确线性化的非线性智能控制策略,首先通过选择合适的输出函数、坐标变换,将不做任何简化的3阶MMC-STATCOM非线性模型转化为一个可控的Brunovsky标准型线性系统,并通过数学理论证明了该模型满足精确线性化条件。然后采用改进的粒子群算法配置其反馈增益矩阵,利用积分滑模控制计算其平衡点。最后通过状态反馈使各个状态变量快速收敛至平衡点。将该控制策略与传统PI控制、LQR状态反馈控制通过硬件在环实时仿真平台进行对比实验,结果表明该控制策略具有更好的动态特性、暂态稳定性、鲁棒性,尤其适用于运行环境发生大扰动时。此外,该控制策略的设计过程可以拓展应用于其他类型的柔性交流输电装置。
文摘The principle of laser optical feedback microscope was presented and demonstrated. Three methods to advance the vertical resolution of laser optical feedback microscope were experimentally studied. The first one is to detect the two polarized lights’ intensities separately with a Wollaston prism instead of to detect the whole light’s intensity. The second is that both of the two orthogonally polarized lights of a birefringent dual frequency laser are fed back. The third one is that only one of the orthogonally polarized lights is fed back. The experimental results show that the modes competition between orthogonally polarized lights can be used to improve the vertical resolution of laser optical feedback microscope effectively.
基金supported by the National Natural Science Foundation of China(11502288)
文摘A decoupled nonsingular terminal sliding mode control（DNTSMC） approach is proposed to address the tracking control problem of affine nonlinear systems.A nonsingular terminal sliding mode control（NTSMC） method is presented,in which the nonsingular terminal sliding surface is defined as a special nonsingular terminal function and the convergence time of the system states can be specified.The affine nonlinear system is firstly decoupled into linear subsystems via feedback linearization.Then,a nonsingular terminal sliding surface is defined and the NTSMC method is applied to each subsystem separately to ensure the finite time convergence of the closed-loop system.The verification example is given to demonstrate the effectiveness and robustness of the proposed approach.The proposed approach exhibits a considerable advantage in terms of faster tracking error convergence and less chattering compared with the conventional sliding mode control（CSMC）.
