In this paper, we discuss some analytic properties of hyperbolic tangent function and estimate some approximation errors of neural network operators with the hyperbolic tan- gent activation function. Firstly, an equat...In this paper, we discuss some analytic properties of hyperbolic tangent function and estimate some approximation errors of neural network operators with the hyperbolic tan- gent activation function. Firstly, an equation of partitions of unity for the hyperbolic tangent function is given. Then, two kinds of quasi-interpolation type neural network operators are con- structed to approximate univariate and bivariate functions, respectively. Also, the errors of the approximation are estimated by means of the modulus of continuity of function. Moreover, for approximated functions with high order derivatives, the approximation errors of the constructed operators are estimated.展开更多
This paper investigates the problem of global/semi-global finite-time consensus for integrator-type multi-agent sys-tems.New hyperbolic tangent function-based protocols are pro-posed to achieve global and semi-global ...This paper investigates the problem of global/semi-global finite-time consensus for integrator-type multi-agent sys-tems.New hyperbolic tangent function-based protocols are pro-posed to achieve global and semi-global finite-time consensus for both single-integrator and double-integrator multi-agent systems with leaderless undirected and leader-following directed commu-nication topologies.These new protocols not only provide an explicit upper-bound estimate for the settling time,but also have a user-prescribed bounded control level.In addition,compared to some existing results based on the saturation function,the pro-posed approach considerably simplifies the protocol design and the stability analysis.Illustrative examples and an application demonstrate the effectiveness of the proposed protocols.展开更多
Rotating Space Slender Flexible Structures(RSSFS)are extensively utilized in space operations because of their light weight,mobility,and low energy consumption.To realize the accurate space operation of the RSSFS,it i...Rotating Space Slender Flexible Structures(RSSFS)are extensively utilized in space operations because of their light weight,mobility,and low energy consumption.To realize the accurate space operation of the RSSFS,it is necessary to establish a precise mechanical model and develop a control algorithm with high precision.However,with the application of traditional control strategies,the RSSFS often suffers from the chattering phenomenon,which will aggravate structure vibration.In this paper,novel deformation description is put forward to balance modeling accuracy and computational efficiency of the RSSFS,which is better appropriate for real-time control.Besides,the Neural Network Sliding Mode Control(NNSMC)strategy modified by the hyperbolic tangent(tanh)function is put forward to compensate for modeling errors and reduce the chattering phenomenon,thereby improving the trajectory tracking accuracy of the RSSFS.Firstly,a mathematical model for the RSSFS is developed according to the novel deformation description and the vibration theory of flexible structure.Comparison of the deformation accuracy between different models proves that the novel modeling method proposed has high modeling accuracy.Next,the universal approximation property of the Radial Basis Function(RBF)neural network is put forward to determine and compensate for modeling errors,which consist of higher-order modes and the uncertainties of external disturbances.In addition,the tanh function is proposed as the reaching law in the conventional NNSMC strategy to suppress driving torque oscillation.The control law of modified NNSMC strategy and the adaptive law of weight coefficients are developed according to the Lyapunov theorem to guarantee the RSSFS stability.Finally,the simulation and physical experimental tests of the RSSFS with different control strategies are conducted.Experimental results show that the control law according to the novel deformation description and the modified NNSMC strategy can obtain accurate tracking of the rotation and reduce the vibration of the RSSFS simultaneously.展开更多
Support vector machines （SVMs） have been intensively applied in the domains of speech recognmon, text categorization, and faults detection. However, the practical application of SVMs is limited by the non-smooth fea...Support vector machines （SVMs） have been intensively applied in the domains of speech recognmon, text categorization, and faults detection. However, the practical application of SVMs is limited by the non-smooth feature of objective function. To overcome this problem, a novel smooth function based on the geometry of circle tangent is constructed. It smoothes the non-differentiable term of unconstrained SVM, and also proposes a circle tangent smooth SVM （CTSSVM）. Compared with other smooth approaching functions, its smooth precision had an obvious improvement. Theoretical analysis proved the global convergence of CTSSVM. Numerical experiments and comparisons showed CTSSVM had better classification and learning efficiency than competitive baselines.展开更多
The objective of this study was to achieve a better control effect of the controller on the liquid level of the liquefied natural gas(LNG)carrier and to achieve the goal of energy saving and carbon reduction.This pape...The objective of this study was to achieve a better control effect of the controller on the liquid level of the liquefied natural gas(LNG)carrier and to achieve the goal of energy saving and carbon reduction.This paper took the loaded square tank of an S175 highspeed container ship as the research plant,combined with the closed-loop gain-shaping algorithm(CGSA)and nonlinear modification technology to further optimize the controller.We initially employed a third-order CGSA approach in formulating the foundation of our linear controller.Subsequently,we introduced a non-linear modification to this controller by harnessing the power of the hyperbolic tangent function,and the control effect is verified by the MATLAB simulation experiment.Based on the outcomes of MATLAB simulations,by integrating the third-order CGSA technique and introducing non-linear modification through the hyperbolic tangent function,we observed a significant enhancement in the controller’s performance.Specifically,it outperformed the traditional PID controller by a substantial margin,demonstrating a remarkable 19%boost in control efficacy.Additionally,it provides better energy savings than the non-linear controller.The controller designed in this paper has a better control effect on the liquid tank-level control of LNG ships,the control process is more energy-saving and the purpose of carbon reduction is realized.展开更多
针对目前定步长和变步长最小均方(Least Mean Square,LMS)算法在设计低通滤波器时面临稳态精度和响应速度二者无法同时保障的问题,设计了一种基于改进变步长LMS算法的自适应滤波器。为获得较高的稳态精度和响应速度,该算法设计过程中引...针对目前定步长和变步长最小均方(Least Mean Square,LMS)算法在设计低通滤波器时面临稳态精度和响应速度二者无法同时保障的问题,设计了一种基于改进变步长LMS算法的自适应滤波器。为获得较高的稳态精度和响应速度,该算法设计过程中引入了改进双曲正切函数用以实现对步长因子及误差信号的连续调节。利用MATLAB/Simulink仿真软件对改进变步长LMS算法下的自适应滤波器进行仿真验证。结果表明,在该算法下设计的滤波器不仅能够响应速度快,而且还能获得较高的稳态精度。展开更多
基金Supported by the National Natural Science Foundation of China(61179041,61272023,and 11401388)
文摘In this paper, we discuss some analytic properties of hyperbolic tangent function and estimate some approximation errors of neural network operators with the hyperbolic tan- gent activation function. Firstly, an equation of partitions of unity for the hyperbolic tangent function is given. Then, two kinds of quasi-interpolation type neural network operators are con- structed to approximate univariate and bivariate functions, respectively. Also, the errors of the approximation are estimated by means of the modulus of continuity of function. Moreover, for approximated functions with high order derivatives, the approximation errors of the constructed operators are estimated.
基金supported by the National Natural Science Foundation of China(62073019)。
文摘This paper investigates the problem of global/semi-global finite-time consensus for integrator-type multi-agent sys-tems.New hyperbolic tangent function-based protocols are pro-posed to achieve global and semi-global finite-time consensus for both single-integrator and double-integrator multi-agent systems with leaderless undirected and leader-following directed commu-nication topologies.These new protocols not only provide an explicit upper-bound estimate for the settling time,but also have a user-prescribed bounded control level.In addition,compared to some existing results based on the saturation function,the pro-posed approach considerably simplifies the protocol design and the stability analysis.Illustrative examples and an application demonstrate the effectiveness of the proposed protocols.
基金Supported by the Applied Basic Research Program of Liaoning Province,China(No.2023JH2/101300159)the National Natural Science Foundation of China(No.52275090).
文摘Rotating Space Slender Flexible Structures(RSSFS)are extensively utilized in space operations because of their light weight,mobility,and low energy consumption.To realize the accurate space operation of the RSSFS,it is necessary to establish a precise mechanical model and develop a control algorithm with high precision.However,with the application of traditional control strategies,the RSSFS often suffers from the chattering phenomenon,which will aggravate structure vibration.In this paper,novel deformation description is put forward to balance modeling accuracy and computational efficiency of the RSSFS,which is better appropriate for real-time control.Besides,the Neural Network Sliding Mode Control(NNSMC)strategy modified by the hyperbolic tangent(tanh)function is put forward to compensate for modeling errors and reduce the chattering phenomenon,thereby improving the trajectory tracking accuracy of the RSSFS.Firstly,a mathematical model for the RSSFS is developed according to the novel deformation description and the vibration theory of flexible structure.Comparison of the deformation accuracy between different models proves that the novel modeling method proposed has high modeling accuracy.Next,the universal approximation property of the Radial Basis Function(RBF)neural network is put forward to determine and compensate for modeling errors,which consist of higher-order modes and the uncertainties of external disturbances.In addition,the tanh function is proposed as the reaching law in the conventional NNSMC strategy to suppress driving torque oscillation.The control law of modified NNSMC strategy and the adaptive law of weight coefficients are developed according to the Lyapunov theorem to guarantee the RSSFS stability.Finally,the simulation and physical experimental tests of the RSSFS with different control strategies are conducted.Experimental results show that the control law according to the novel deformation description and the modified NNSMC strategy can obtain accurate tracking of the rotation and reduce the vibration of the RSSFS simultaneously.
文摘Support vector machines （SVMs） have been intensively applied in the domains of speech recognmon, text categorization, and faults detection. However, the practical application of SVMs is limited by the non-smooth feature of objective function. To overcome this problem, a novel smooth function based on the geometry of circle tangent is constructed. It smoothes the non-differentiable term of unconstrained SVM, and also proposes a circle tangent smooth SVM （CTSSVM）. Compared with other smooth approaching functions, its smooth precision had an obvious improvement. Theoretical analysis proved the global convergence of CTSSVM. Numerical experiments and comparisons showed CTSSVM had better classification and learning efficiency than competitive baselines.
基金supported by the National Science Foundation of China(Grant No.51679024)Dalian Innovation Team Support Plan in the Key Research Field(Grant No.2020RT08)+1 种基金Doctoral Research Initial Fund Project of Liaoning Province(Grant No.2021-BS-078)Dalian Maritime University University-level Team"Open Ranking"Project(Grant No.3132023502).
文摘The objective of this study was to achieve a better control effect of the controller on the liquid level of the liquefied natural gas(LNG)carrier and to achieve the goal of energy saving and carbon reduction.This paper took the loaded square tank of an S175 highspeed container ship as the research plant,combined with the closed-loop gain-shaping algorithm(CGSA)and nonlinear modification technology to further optimize the controller.We initially employed a third-order CGSA approach in formulating the foundation of our linear controller.Subsequently,we introduced a non-linear modification to this controller by harnessing the power of the hyperbolic tangent function,and the control effect is verified by the MATLAB simulation experiment.Based on the outcomes of MATLAB simulations,by integrating the third-order CGSA technique and introducing non-linear modification through the hyperbolic tangent function,we observed a significant enhancement in the controller’s performance.Specifically,it outperformed the traditional PID controller by a substantial margin,demonstrating a remarkable 19%boost in control efficacy.Additionally,it provides better energy savings than the non-linear controller.The controller designed in this paper has a better control effect on the liquid tank-level control of LNG ships,the control process is more energy-saving and the purpose of carbon reduction is realized.
文摘针对目前定步长和变步长最小均方(Least Mean Square,LMS)算法在设计低通滤波器时面临稳态精度和响应速度二者无法同时保障的问题,设计了一种基于改进变步长LMS算法的自适应滤波器。为获得较高的稳态精度和响应速度,该算法设计过程中引入了改进双曲正切函数用以实现对步长因子及误差信号的连续调节。利用MATLAB/Simulink仿真软件对改进变步长LMS算法下的自适应滤波器进行仿真验证。结果表明,在该算法下设计的滤波器不仅能够响应速度快,而且还能获得较高的稳态精度。
