This paper presents a method to design a control scheme for nonlinear systems using fuzzy optimal control.In the design process,the nonlinear system is first converted into local subsystems using sector non linearity ...This paper presents a method to design a control scheme for nonlinear systems using fuzzy optimal control.In the design process,the nonlinear system is first converted into local subsystems using sector non linearity approach of Takagi Sugeno(T S)fuzzy modeling.For each local subsystem,an optimal control is designed.Then,the parameters of local controllers are defuzzified to construct a global optimal controller.To prove the effectiveness of this control scheme,simulations are performed using the mathematical model of Esso Osaka tanker ship for set point regulation with and without disturbance and reference tracking.In addition,the simulation results are compared with that of a PID controller for further verification and validation.It has been shown that the proposed optimal controller can be used for the nonlinear ship steering with good rise time,zero steady state error and fast settling time.展开更多
A robust H∞sampled-data stabilization problem for nonlinear dynamic positioning(DP) ships with Takagi-Sugeno(T-S) fuzzy models is discussed in this paper. Input delay approach is used to convert the sampleddata DP sh...A robust H∞sampled-data stabilization problem for nonlinear dynamic positioning(DP) ships with Takagi-Sugeno(T-S) fuzzy models is discussed in this paper. Input delay approach is used to convert the sampleddata DP ship system to a fuzzy system with time-varying delay. Adequate conditions are derived to determine the system's asymptotical stability and achieve H∞performance via Lyapunov stability theorems. Then, the fuzzy sampled-data controller is obtained by analyzing the stabilization condition. Simulation result shows that the proposed method and the designed controller for a DP ship are effective so that the DP ship can maintain the desired position, heading and velocities in the existence of varying environment disturbances.展开更多
在海洋重力测量中,厄特沃什(E tv s)改正误差一直是影响测量精度的主要误差源。对测量过程的分析可以发现,原始采集的重力值实际上是经过低通滤波后一段时间内的平均重力变化,而一般的E tv s改正方法计算所得的只是某一时刻的改正值,这...在海洋重力测量中,厄特沃什(E tv s)改正误差一直是影响测量精度的主要误差源。对测量过程的分析可以发现,原始采集的重力值实际上是经过低通滤波后一段时间内的平均重力变化,而一般的E tv s改正方法计算所得的只是某一时刻的改正值,这种差异导致了重力数据精度的下降。针对这种情况,提出了合理的滤波E tv s改正方法,使改正值和重力值达到了完全对应。最后以L&R的S型海洋重力仪的测量数据为例,具体地说明了这种新方法的改正效果。展开更多
基金supported in part by the National Natural Science Foundation of China (No. 61751210)the Jiangsu Natural Science Foundation of China (No. BK20171417)the Fundamental Research Funds for the Central Universities(No. NG2019002)
文摘This paper presents a method to design a control scheme for nonlinear systems using fuzzy optimal control.In the design process,the nonlinear system is first converted into local subsystems using sector non linearity approach of Takagi Sugeno(T S)fuzzy modeling.For each local subsystem,an optimal control is designed.Then,the parameters of local controllers are defuzzified to construct a global optimal controller.To prove the effectiveness of this control scheme,simulations are performed using the mathematical model of Esso Osaka tanker ship for set point regulation with and without disturbance and reference tracking.In addition,the simulation results are compared with that of a PID controller for further verification and validation.It has been shown that the proposed optimal controller can be used for the nonlinear ship steering with good rise time,zero steady state error and fast settling time.
基金the National Natural Science Foundation of China(No.51579114)the Project of New Century Excellent Talents of Colleges and Universities of Fujian Province(No.JA12181)the Project of Young and Middle-Aged Teacher Education of Fujian Province(No.JAT170309)
文摘A robust H∞sampled-data stabilization problem for nonlinear dynamic positioning(DP) ships with Takagi-Sugeno(T-S) fuzzy models is discussed in this paper. Input delay approach is used to convert the sampleddata DP ship system to a fuzzy system with time-varying delay. Adequate conditions are derived to determine the system's asymptotical stability and achieve H∞performance via Lyapunov stability theorems. Then, the fuzzy sampled-data controller is obtained by analyzing the stabilization condition. Simulation result shows that the proposed method and the designed controller for a DP ship are effective so that the DP ship can maintain the desired position, heading and velocities in the existence of varying environment disturbances.
文摘在海洋重力测量中,厄特沃什(E tv s)改正误差一直是影响测量精度的主要误差源。对测量过程的分析可以发现,原始采集的重力值实际上是经过低通滤波后一段时间内的平均重力变化,而一般的E tv s改正方法计算所得的只是某一时刻的改正值,这种差异导致了重力数据精度的下降。针对这种情况,提出了合理的滤波E tv s改正方法,使改正值和重力值达到了完全对应。最后以L&R的S型海洋重力仪的测量数据为例,具体地说明了这种新方法的改正效果。
