The selection of weighting matrix in design of the linear quadratic optimal controller is an important topic in the control theory. In this paper, an approach based on genetic algorithm is presented for selecting the ...The selection of weighting matrix in design of the linear quadratic optimal controller is an important topic in the control theory. In this paper, an approach based on genetic algorithm is presented for selecting the weighting matrix for the optimal controller. Genetic algorithm is adaptive heuristic search algorithm premised on the evolutionary ideas of natural selection and genetic. In this algorithm, the fitness function is used to evaluate individuals and reproductive success varies with fitness. In the design of the linear quadratic optimal controller, the fitness function has relation to the anticipated step response of the system. Not only can the controller designed by this approach meet the demand of the performance indexes of linear quadratic controller, but also satisfy the anticipated step response of close-loop system. The method possesses a higher calculating efficiency and provides technical support for the optimal controller in engineering application. The simulation of a three-order single-input single-output (SISO) system has demonstrated the feasibility and validity of the approach.展开更多
Using e-beam evaporation, the ellipsometric parameters of thick transparent films are studied with the modified analysis method for the SiO 2 film samples deposited onto the Si substrate. The ellipsometric parameters ...Using e-beam evaporation, the ellipsometric parameters of thick transparent films are studied with the modified analysis method for the SiO 2 film samples deposited onto the Si substrate. The ellipsometric parameters are measured at the incidence angles changing from 50 to 70 and in the 3–4.5 eV photon energy range. The error in the conventional method can be significantly reduced by the modified ellipsometric method considering the spatial effect to show good agreement between the theoretical and experimental results. The new method presented in this letter can be applied to other optical measurement of the periodic or non-periodic film structures.展开更多
文摘The selection of weighting matrix in design of the linear quadratic optimal controller is an important topic in the control theory. In this paper, an approach based on genetic algorithm is presented for selecting the weighting matrix for the optimal controller. Genetic algorithm is adaptive heuristic search algorithm premised on the evolutionary ideas of natural selection and genetic. In this algorithm, the fitness function is used to evaluate individuals and reproductive success varies with fitness. In the design of the linear quadratic optimal controller, the fitness function has relation to the anticipated step response of the system. Not only can the controller designed by this approach meet the demand of the performance indexes of linear quadratic controller, but also satisfy the anticipated step response of close-loop system. The method possesses a higher calculating efficiency and provides technical support for the optimal controller in engineering application. The simulation of a three-order single-input single-output (SISO) system has demonstrated the feasibility and validity of the approach.
基金supported by the National Natural Science Foundation of China (No. 60938004)the STCSM Project of China (No. 08DJ1400302)+1 种基金the Shanghai Municipal Education Commission Fund (No. 10YZ213)the Leading Academic Discipline Project of Shanghai Municipal Education Commission (No. J5180Q)
文摘Using e-beam evaporation, the ellipsometric parameters of thick transparent films are studied with the modified analysis method for the SiO 2 film samples deposited onto the Si substrate. The ellipsometric parameters are measured at the incidence angles changing from 50 to 70 and in the 3–4.5 eV photon energy range. The error in the conventional method can be significantly reduced by the modified ellipsometric method considering the spatial effect to show good agreement between the theoretical and experimental results. The new method presented in this letter can be applied to other optical measurement of the periodic or non-periodic film structures.
