A new chaotic genetic hybrid algorithm(CGHA) based on float point coding was put forward in this paper.Firstly,it used chaos optimization to search coarsely and produced a better initial population.Then,a power functi...A new chaotic genetic hybrid algorithm(CGHA) based on float point coding was put forward in this paper.Firstly,it used chaos optimization to search coarsely and produced a better initial population.Then,a power function carrier was adopted to improve the ergodicity and the sufficiency of the chaos optimization.Secondly,the genetic algorithm(GA) was used to search finely and guaranteed the population's evolution.To avoid the search being trapped in local minimum,a chaos degenerate mutation operator was designed to make the search converge to a global optimum quickly.Finally,CGHA was used to solve a typical mechanical optimization problem of shear stress checking for a cylinder helix spring.Compared with traditional penalty function method,chaos-Powell hybrid algorithm and standard GA,CGHA shows better performance in solution precision and convergence speed than those of the algorithms.Therefore,CGHA is a new effective way to solve the problems in mechanical optimization design.展开更多
The paper presents a method of the runner blades design for simple case of hydraulic turbine. Two differently shaped channels of meridional cross section were examined. The quantitative evaluation was performed by mea...The paper presents a method of the runner blades design for simple case of hydraulic turbine. Two differently shaped channels of meridional cross section were examined. The quantitative evaluation was performed by means of 3D algorithm. It has been found that, divergent runner prevails convergent from dissipation point of view. Although, the influence of draft tube has not been analyzed, the presented method is important for the designers of low head hydraulic turbines which are not the matter of standardization due to variety of environmental conditions.展开更多
Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a tran...Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a transporter of ore. This paper proposes a distributed system that realizes the excavation and transport functions with separated vehicles, an excavator and a transporter. In addition, this research proposes a mining map and configurations suitable for the proposed distributed system. To evaluate the productivity of the proposed system, a simulation environment has been developed. Analysis using the simulator reveals what performance factors of the excavator and the transporter have large impacts on the productivity. Simulation results also demonstrate the difference of potential between LHD system and the distributed system that can be explained based on their functions allocation.展开更多
The harvesting process of the olive tree is mainly performed by manual means,because traditional olive orchards(the main planting typology)are formed of irregular,large-canopy trees that are very difficult to harvest ...The harvesting process of the olive tree is mainly performed by manual means,because traditional olive orchards(the main planting typology)are formed of irregular,large-canopy trees that are very difficult to harvest mechanically.For that reason,the cost of harvesting is very high,and it threatens the future of these plantations whose conversion to other more modern layouts is not always possible due to several limitations.The introduction of a harvester may represent the technological change that is the key factor for improved competitiveness.The main purpose of this work was to develop a harvester based on canopy shaker technology for work on irregular,large trees in a circular path.The design of the harvester was based on a determination of tree geometry,together with tree training.Field tests were used to determine machine-tree interaction,and to evaluate the removal,catch frame and driven systems.The proposed innovation allowed the fully mechanical harvest of previously planted trees with a removal efficiency of over 84%,achieving an effective field capacity of 0.21 hm^(2)/h.Although the results so far have been promising,further improvements are advisable in machine and tree adaptation.展开更多
基金Sponsored by the National Natural Science Foundation of China (50875186)the Research and Development Projects of Tianjin University of Technology and Education (KJ2008028,KJ2008043)
文摘A new chaotic genetic hybrid algorithm(CGHA) based on float point coding was put forward in this paper.Firstly,it used chaos optimization to search coarsely and produced a better initial population.Then,a power function carrier was adopted to improve the ergodicity and the sufficiency of the chaos optimization.Secondly,the genetic algorithm(GA) was used to search finely and guaranteed the population's evolution.To avoid the search being trapped in local minimum,a chaos degenerate mutation operator was designed to make the search converge to a global optimum quickly.Finally,CGHA was used to solve a typical mechanical optimization problem of shear stress checking for a cylinder helix spring.Compared with traditional penalty function method,chaos-Powell hybrid algorithm and standard GA,CGHA shows better performance in solution precision and convergence speed than those of the algorithms.Therefore,CGHA is a new effective way to solve the problems in mechanical optimization design.
文摘The paper presents a method of the runner blades design for simple case of hydraulic turbine. Two differently shaped channels of meridional cross section were examined. The quantitative evaluation was performed by means of 3D algorithm. It has been found that, divergent runner prevails convergent from dissipation point of view. Although, the influence of draft tube has not been analyzed, the presented method is important for the designers of low head hydraulic turbines which are not the matter of standardization due to variety of environmental conditions.
文摘Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a transporter of ore. This paper proposes a distributed system that realizes the excavation and transport functions with separated vehicles, an excavator and a transporter. In addition, this research proposes a mining map and configurations suitable for the proposed distributed system. To evaluate the productivity of the proposed system, a simulation environment has been developed. Analysis using the simulator reveals what performance factors of the excavator and the transporter have large impacts on the productivity. Simulation results also demonstrate the difference of potential between LHD system and the distributed system that can be explained based on their functions allocation.
基金The authors gratefully acknowledge financial support from the Spanish Ministry of Economy and Competitiveness(PCP Mecaolivar),and the Spanish Olive Oil Interprofessional Organisation.
文摘The harvesting process of the olive tree is mainly performed by manual means,because traditional olive orchards(the main planting typology)are formed of irregular,large-canopy trees that are very difficult to harvest mechanically.For that reason,the cost of harvesting is very high,and it threatens the future of these plantations whose conversion to other more modern layouts is not always possible due to several limitations.The introduction of a harvester may represent the technological change that is the key factor for improved competitiveness.The main purpose of this work was to develop a harvester based on canopy shaker technology for work on irregular,large trees in a circular path.The design of the harvester was based on a determination of tree geometry,together with tree training.Field tests were used to determine machine-tree interaction,and to evaluate the removal,catch frame and driven systems.The proposed innovation allowed the fully mechanical harvest of previously planted trees with a removal efficiency of over 84%,achieving an effective field capacity of 0.21 hm^(2)/h.Although the results so far have been promising,further improvements are advisable in machine and tree adaptation.
