An IMC-PID controller was proposed for unstable second-order time delay system which shows the characteristics of inverse response(RHP zero). A plot of Ms versus λ was suggested to calculate the suitable tuning param...An IMC-PID controller was proposed for unstable second-order time delay system which shows the characteristics of inverse response(RHP zero). A plot of Ms versus λ was suggested to calculate the suitable tuning parameter λ, which provides a trade-off between performance and robustness. Six different forms of process models were selected from literature to show the applicability of the present method. Performance of controller was calculated by ITAE and total variation TV and compared with recently published tuning rules. Undesirable overshoot was removed by using a set-point weighting parameter. Robustness was tested by introducing a perturbation into the various model parameters and closed-loop results show that the designed controller is robust in the case of model uncertainty. The proposed method shows an overall better closed-loop response as compared to other recently reported methods.展开更多
Using outward rotations, we obtain an approximation algorithm for MAXn/2-UNCUT problem, i.e., partitioning the vertices of a weighted graph into two blocks of equalcardinality such that the total weight of edges that ...Using outward rotations, we obtain an approximation algorithm for MAXn/2-UNCUT problem, i.e., partitioning the vertices of a weighted graph into two blocks of equalcardinality such that the total weight of edges that do not cross the cut is maximized. In manyinteresting cases, the algorithm performs better than the algorithms of Ye and of Halperin andZwick. The main tool used to obtain this result is semidefinite programming.展开更多
基金India (MHRD, India) for providing financial support
文摘An IMC-PID controller was proposed for unstable second-order time delay system which shows the characteristics of inverse response(RHP zero). A plot of Ms versus λ was suggested to calculate the suitable tuning parameter λ, which provides a trade-off between performance and robustness. Six different forms of process models were selected from literature to show the applicability of the present method. Performance of controller was calculated by ITAE and total variation TV and compared with recently published tuning rules. Undesirable overshoot was removed by using a set-point weighting parameter. Robustness was tested by introducing a perturbation into the various model parameters and closed-loop results show that the designed controller is robust in the case of model uncertainty. The proposed method shows an overall better closed-loop response as compared to other recently reported methods.
基金This research is partly supported by Chinese NSF grant 19731001 and National 973 Information Technol- ogy High-Performance Software Program of China with grant No. G1998030401The author gratefully acknowledges the support of K. C. Wong Education
文摘Using outward rotations, we obtain an approximation algorithm for MAXn/2-UNCUT problem, i.e., partitioning the vertices of a weighted graph into two blocks of equalcardinality such that the total weight of edges that do not cross the cut is maximized. In manyinteresting cases, the algorithm performs better than the algorithms of Ye and of Halperin andZwick. The main tool used to obtain this result is semidefinite programming.