The IMC(Internal Model Control) controller based on robust tuning can improve the robustness and dynamic performance of the system.In this paper,the robustness degree of the control system is investigated based on Max...The IMC(Internal Model Control) controller based on robust tuning can improve the robustness and dynamic performance of the system.In this paper,the robustness degree of the control system is investigated based on Maximum Sensitivity(Ms) in depth.And the analytical relationship is obtained between the robustness specification and controller parameters,which gives a clear design criterion to robust IMC controller.Moreover,a novel and simple IMC-PID(Proportional-Integral-Derivative) tuning method is proposed by converting the IMC controller to PID form in terms of the time domain rather than the frequency domain adopted in some conventional IMC-based methods.Hence,the presented IMC-PID gives a good performance with a specific robustness degree.The new IMC-PID method is compared with other classical IMC-PID rules,showing the flexibility and feasibility for a wide range of plants.展开更多
Multi-stand roll forming is a process that has very complicated deformation behaviour and shows significant nonlinearity.In this paper, the sensitivity analysis of parameters for multi-stand roll forming was performed...Multi-stand roll forming is a process that has very complicated deformation behaviour and shows significant nonlinearity.In this paper, the sensitivity analysis of parameters for multi-stand roll forming was performed via a new booting finite element method(FEM) model.Compared with the most of simulation, the new model is more consistent with production process and can account for the effects of roll rotating speed.Based on the model, the process of an open section channel formed with 10 passes was simulated and the sensitivity analysis was conducted with orthogonal experiment design combined FEM model.The multi-stand roll forming process can be efficiently analyzed by the new booting model.And sensitivity analysis shows the hardening exponent plays an important role in controlling the quality of the products.展开更多
In this short review, I discuss the sensitivity of the generation of the light and the life-relevant elements such as carbon and oxygen under changes of the parame- ters of the Standard Model pertinent to nuclear phys...In this short review, I discuss the sensitivity of the generation of the light and the life-relevant elements such as carbon and oxygen under changes of the parame- ters of the Standard Model pertinent to nuclear physics. Chiral effective field theory allows for a systematic and precise description of the forces between two, three and four nucleons. In this framework, variations under the light quark masses and the electromagnetic fine-structure constant can also be consistently calculated. Combining chiral nuclear effective field theory with Monte Carlo simulations allows to further calculate the properties of nuclei, in particular of the Hoyle state in carbon, that plays a crucial role in the gener- ation of the life-relevant elements in hot, old stars. The dependence of the triple-alpha process on the fundamental constants of nature is calculated, and some implications for our anthropic view of the Universe are discussed.展开更多
基金Supported by the National Natural Science Foundation of China（61273132）Doctoral Fund of Ministry of Education of China（20110010110010）
文摘The IMC(Internal Model Control) controller based on robust tuning can improve the robustness and dynamic performance of the system.In this paper,the robustness degree of the control system is investigated based on Maximum Sensitivity(Ms) in depth.And the analytical relationship is obtained between the robustness specification and controller parameters,which gives a clear design criterion to robust IMC controller.Moreover,a novel and simple IMC-PID(Proportional-Integral-Derivative) tuning method is proposed by converting the IMC controller to PID form in terms of the time domain rather than the frequency domain adopted in some conventional IMC-based methods.Hence,the presented IMC-PID gives a good performance with a specific robustness degree.The new IMC-PID method is compared with other classical IMC-PID rules,showing the flexibility and feasibility for a wide range of plants.
基金the National Natural Science Foundation of China (No. 50605043)
文摘Multi-stand roll forming is a process that has very complicated deformation behaviour and shows significant nonlinearity.In this paper, the sensitivity analysis of parameters for multi-stand roll forming was performed via a new booting finite element method(FEM) model.Compared with the most of simulation, the new model is more consistent with production process and can account for the effects of roll rotating speed.Based on the model, the process of an open section channel formed with 10 passes was simulated and the sensitivity analysis was conducted with orthogonal experiment design combined FEM model.The multi-stand roll forming process can be efficiently analyzed by the new booting model.And sensitivity analysis shows the hardening exponent plays an important role in controlling the quality of the products.
基金supported in part by DFG and NSFC (Sino-German CRC 110)Helmholtz Association (contract VHVI-417)+2 种基金BMBF (grant 05P12PDFTE)the EU (Hadron Physics3 project)LENPIC (DEC-2103/10/M/ST2/00420)
文摘In this short review, I discuss the sensitivity of the generation of the light and the life-relevant elements such as carbon and oxygen under changes of the parame- ters of the Standard Model pertinent to nuclear physics. Chiral effective field theory allows for a systematic and precise description of the forces between two, three and four nucleons. In this framework, variations under the light quark masses and the electromagnetic fine-structure constant can also be consistently calculated. Combining chiral nuclear effective field theory with Monte Carlo simulations allows to further calculate the properties of nuclei, in particular of the Hoyle state in carbon, that plays a crucial role in the gener- ation of the life-relevant elements in hot, old stars. The dependence of the triple-alpha process on the fundamental constants of nature is calculated, and some implications for our anthropic view of the Universe are discussed.
