Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predi...Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predicting the decrease of speed on a ship operating at sea. Furthermore, it is also significant to investigate the added resistance for a ship functioning in short waves of large modern ships. The researcher presents an estimation formula for the calculation of an added resistance study in short waves derived from the reflection law. An improved method has been proposed to calculate the added resistance due to ship motions, which applies the radiated energy theory along with the strip method. This procedure is based on an extended integral equation （EIE） method, which was used for solving the hydrodynamic coefficients without effects of the irregular frequency. Next, a combined method was recommended for the estimation of added resistance for a ship in the whole wave length range. The comparison data with other experiments indicate the method presented in the paper provides satisfactory results for large blunt ship.展开更多
In this study, the multistep method is applied to the STF system. This method has been tested on the STF system, which is a three-dimensional system of ODE with quadratic nonlinearities. A computer based Matlab progra...In this study, the multistep method is applied to the STF system. This method has been tested on the STF system, which is a three-dimensional system of ODE with quadratic nonlinearities. A computer based Matlab program has been developed in order to solve the STF system. Stable and unstable position of the system has been analyzed graphically and finally a comparison as well as accuracy between two-step sizes with detail. Newton’s method has been applied to show the best convergence of this system.展开更多
现代控制论与控制实际之间存在一些"鸿沟",根据PID (Proportional-integral-derivative)控制器具有良好抗扰性的事实,提出了一种基于PID的二阶内反馈控制器(Second order of internal feedback controller, SO-IFC).基于在新...现代控制论与控制实际之间存在一些"鸿沟",根据PID (Proportional-integral-derivative)控制器具有良好抗扰性的事实,提出了一种基于PID的二阶内反馈控制器(Second order of internal feedback controller, SO-IFC).基于在新型"高效"滤波方法上的一些进展,将一种新型正弦跟踪滤波方法 (New sinusoid tracking filter, NSTF)运用于SO-IFC控制回路的噪声干扰滤波.针对被控对象的准确数学模型难以获取的问题,将一种根据过程增益(Process gain, PG)和过程总滞后(Process all lag, PAL)的工程参数整定方法 (Engineering parameter tuning method, EPTM)运用于SO-IFC参数的整定,降低了SO-IFC参数整定的难度.将SO-IFC运用于大滞后过程的控制,具有良好的控制性能包括良好的扰动抑制性能.数学分析、仿真实验和实际应用的结果验证了文中所提出观点和方法的正确性和有效性.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.51079032 the Outstanding Youth Science Foundation of Heilongjiang Province,No.200908
文摘Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predicting the decrease of speed on a ship operating at sea. Furthermore, it is also significant to investigate the added resistance for a ship functioning in short waves of large modern ships. The researcher presents an estimation formula for the calculation of an added resistance study in short waves derived from the reflection law. An improved method has been proposed to calculate the added resistance due to ship motions, which applies the radiated energy theory along with the strip method. This procedure is based on an extended integral equation （EIE） method, which was used for solving the hydrodynamic coefficients without effects of the irregular frequency. Next, a combined method was recommended for the estimation of added resistance for a ship in the whole wave length range. The comparison data with other experiments indicate the method presented in the paper provides satisfactory results for large blunt ship.
文摘In this study, the multistep method is applied to the STF system. This method has been tested on the STF system, which is a three-dimensional system of ODE with quadratic nonlinearities. A computer based Matlab program has been developed in order to solve the STF system. Stable and unstable position of the system has been analyzed graphically and finally a comparison as well as accuracy between two-step sizes with detail. Newton’s method has been applied to show the best convergence of this system.
文摘现代控制论与控制实际之间存在一些"鸿沟",根据PID (Proportional-integral-derivative)控制器具有良好抗扰性的事实,提出了一种基于PID的二阶内反馈控制器(Second order of internal feedback controller, SO-IFC).基于在新型"高效"滤波方法上的一些进展,将一种新型正弦跟踪滤波方法 (New sinusoid tracking filter, NSTF)运用于SO-IFC控制回路的噪声干扰滤波.针对被控对象的准确数学模型难以获取的问题,将一种根据过程增益(Process gain, PG)和过程总滞后(Process all lag, PAL)的工程参数整定方法 (Engineering parameter tuning method, EPTM)运用于SO-IFC参数的整定,降低了SO-IFC参数整定的难度.将SO-IFC运用于大滞后过程的控制,具有良好的控制性能包括良好的扰动抑制性能.数学分析、仿真实验和实际应用的结果验证了文中所提出观点和方法的正确性和有效性.
