Climate change vulnerability assessment is an essential tool for identifying regions that are most susceptible to the impacts of climate change and designing effective adaptation actions that can reduce vulnerability ...Climate change vulnerability assessment is an essential tool for identifying regions that are most susceptible to the impacts of climate change and designing effective adaptation actions that can reduce vulnerability and enhance long-term resilience of these regions.This study explored a framework for climate change vulnerability assessment in the new urban planning process in Jangwani Ward,Tanzania.Specifically,taking flood as an example,this study highlighted the steps and methods for climate change vulnerability assessment in the new urban planning process.In the study area,95 households were selected and interviewed through purposeful sampling.Additionally,10 respondents(4 females and 6 males)were interviewed for Focus Group Discussion(FGD),and 3 respondents(1 female and 2 males)were selected for Key Informant Interviews(KII)at the Ministry of Lands,Housing and Human Settlements Development.This study indicated that climate change vulnerability assessment framework involves the assessment of climatic hazards,risk elements,and adaptive capacity,and the determination of vulnerability levels.The average hazard risk rating of flood was 2.3.Socioeconomic and livelihood activities and physical infrastructures both had the average risk element rating of 3.0,and ecosystems had the average risk element rating of 2.9.Adaptive capacity ratings of knowledge,technology,economy or finance,and institution were 1.6,1.9,1.4,and 2.2,respectively.The vulnerability levels of socioeconomic and livelihood activities and physical infrastructure were very high(4.0).Ecosystems had a high vulnerability level(3.8)to flood.The very high vulnerability level of socioeconomic and livelihood activities was driven by high exposure and sensitivity to risk elements and low adaptive capacity.The study recommends adoption of the new urban planning process including preparation,planning,implementation,and monitoring-evaluation-review phases that integrates climate change vulnerability assessment in all phases.展开更多
Computer-aided block assembly process planning based on rule-reasoning are developed in order to improve the assembly efficiency and implement the automated block assembly process planning generation in shipbuilding. ...Computer-aided block assembly process planning based on rule-reasoning are developed in order to improve the assembly efficiency and implement the automated block assembly process planning generation in shipbuilding. First, weighted directed liaison graph (WDLG) is proposed to represent the model of block assembly process according to the characteristics of assembly relation, and edge list (EL) is used to describe assembly sequences. Shapes and assembly attributes of block parts are analyzed to determine the assembly position and matched parts of parts used frequently. Then, a series of assembly rules are generalized, and assembly sequences for block are obtained by means of rule reasoning. Final, a prototype system of computer-aided block assembly process planning is built. The system has been tested on actual block, and the results were found to be quite efficiency. Meanwhile, the fundament for the automation of block assembly process generation and integration with other systems is established.展开更多
Assembly process planning(APP) for complicated products is a time-consuming and difficult work with conventional method. Virtual assembly process planning(VAPP) provides engineers a new and efficiency way. Previou...Assembly process planning(APP) for complicated products is a time-consuming and difficult work with conventional method. Virtual assembly process planning(VAPP) provides engineers a new and efficiency way. Previous studies in VAPP are almost isolated and dispersive, and have not established a whole understanding and discussed key realization techniques of VAPP from a systemic and integrated view. The integrated virtual assembly process planning(IVAPP) system is a new virtual reality based engineering application, which offers engineers an efficient, intuitive, immersive and integrated method for assembly process planning in a virtual environment. Based on analysis the information integration requirement of VAPP, the architecture of IVAPP is proposed. Through the integrated structure, IVAPP system can realize information integration and workflow controlling. In order to mode/the assembly process in IVAPP, a hierarchical assembly task list(HATL) is presented, in which different assembly tasks for assembling different components are organized into a hierarchical list. A process-oriented automatic geometrical constraint recognition algorithm(AGCR) is proposed, so that geometrical constraints between components can be automatically recognized during the process of interactive assembling. At the same time, a progressive hierarchical reasoning(PHR) model is discussed. AGCR and PHR will greatly reduce the interactive workload. A discrete control node model(DCNM) for cable harness assembly planning in IVAPP is detailed. DCNM converts a cable harness into continuous flexed line segments connected by a series of section center points, and designs can realize cable harness planning through controlling those control nodes. Mechanical assemblies (such as transmission case and engine of automobile) are used to illustrate the feasibility of the proposed method and algorithms. The application of IVAPP system reveals advantages over the traditional assembly process planning method in shortening the time-consumed in assembly planning and in minimizing the handling difficulty, excessive reorientation and dissimilarity of assembly operations.展开更多
Intelligent process planning(PP)is one of the most important components in an intelligent manufacturing system and acts as a bridge between product designing and practical manufacturing.PP is a nondeterministic polyno...Intelligent process planning(PP)is one of the most important components in an intelligent manufacturing system and acts as a bridge between product designing and practical manufacturing.PP is a nondeterministic polynomial-time(NP)-hard problem and,as existing mathematical models are not formulated in linear forms,they cannot be solved well to achieve exact solutions for PP problems.This paper proposes a novel mixed-integer linear programming(MILP)mathematical model by considering the network topology structure and the OR nodes that represent a type of OR logic inside the network.Precedence relationships between operations are discussed by raising three types of precedence relationship matrices.Furthermore,the proposed model can be programmed in commonly-used mathematical programming solvers,such as CPLEX,Gurobi,and so forth,to search for optimal solutions for most open problems.To verify the effectiveness and generality of the proposed model,five groups of numerical experiments are conducted on well-known benchmarks.The results show that the proposed model can solve PP problems effectively and can obtain better solutions than those obtained by the state-ofthe-art algorithms.展开更多
Space emergency launching is to send a satellite into space by using a rapid responsive solid rocket in the bounded time to implement the emergency Earth observation mission.The key and difficult points mainly include...Space emergency launching is to send a satellite into space by using a rapid responsive solid rocket in the bounded time to implement the emergency Earth observation mission.The key and difficult points mainly include the business process construction of launching mission planning,validation of the effectiveness of the launching scheme,etc.This paper pro-poses the agile space emergency launching mission planning simulation and verification method,which systematically con-structs the overall technical framework of space emergency launching mission planning with multi-field area,multi-platform and multi-task parallel under the constraint of resource schedul-ing for the first time.It supports flexible reconstruction of mis-sion planning processes such as launching target planning,tra-jectory planning,path planning,action planning and launching time analysis,and can realize on-demand assembly of operation links under different mission scenarios and different plan condi-tions,so as to quickly modify and generate launching schemes.It supports the fast solution of rocket trajectory data and the accurate analysis of multi-point salvo time window recheck and can realize the fast conflict resolution of launching missions in the dimensions of launching position and launching window sequence.It supports lightweight scenario design,modular flexi-ble simulation,based on launching style,launching platform,launching rules,etc.,can realize the independent mapping of mission planning results to two-dimensional and three-dimen-sional visual simulation models,so as to achieve a smooth con-nection between mission planning and simulation.展开更多
Flexible transfer line(FTL)is now widely used in ma ny manufacturing domains to realize efficiently,high quantity and economic prod uction.These manufacturing domains include automobile,tractor,internal-combu stion en...Flexible transfer line(FTL)is now widely used in ma ny manufacturing domains to realize efficiently,high quantity and economic prod uction.These manufacturing domains include automobile,tractor,internal-combu stion engine,and so on.In today’s competitive business environment,it is vit ally important for machine tool manufacturers to design flexible transfer line m ore effectively and efficiently according to a wider variety of customer demand s.This paper proposes an approach to a bidding-based flexible transfer line sc hematic design system.By analyzing manual FTL design process,the architecture o f flexible transfer line schematic design system(FTLSDS)is established.The syst em consists:of four processes:part feature modeling,process planning,FTL fac i lity layout and FTL evaluation. For FTL schematic design.a five-level proces s planning strategy named hierarchical process planning method is proposed.This method includes selection of manufacturing feature machining operation;part se t-up planning,feature sequencing,operation sequencing and process plan genera ting.The major decision relies on setup planning.According to the proceeding o f the hierarchical process planning,the structure of reasoning is proposed base d on blackboard.Under this paradigm,a cooperative effort between a hybrid coll ection of knowledge sources is possible.Total reasoning task can be divided int o some subtasks,and recursive-reasoning system is formed.It is convenient for process planning with step-by-step solution.Meanwhile,the blackboard is use d as the global data exchange area during all reasoning process.By using modula r technology,special purpose machine tools can be designed more efficiently and rapidly.The framework of machine modular design system to support machine requ irement design for FTL is established.By synthesizing the FTL evaluation criter ia.five evaluation criteria of flexible transfer 1ine schematic design are take n into account.An exampie is supplied to demonstrate and verify the validity an d feasibility of flexible transfer line schematic design approach.展开更多
Production planning models generated by common modeling systems do not involve constraints for process operations, and a solution optimized by these models is called a quasi-optimal plan. The quasi-optimal plan cannot...Production planning models generated by common modeling systems do not involve constraints for process operations, and a solution optimized by these models is called a quasi-optimal plan. The quasi-optimal plan cannot be executed in practice some time for no corresponding operating conditions. In order to determine a practi- cally feasible optimal plan and corresponding operating conditions of fluidized catalytic cracking unit (FCCU), a novel close-loop integrated strategy, including determination of a quasi-optimal plan, search of operating conditions of FCCU and revision of the production planning model, was proposed in this article. In the strategy, a generalized genetic algorithm (GA) coupled with a sequential process simulator of FCCU was applied to search operating conditions implementing the quasi-optimal plan of FCCU and output the optimal individual in the GA search as a final genetic individual. When no corresponding operating conditions were found, the final genetic individual based correction (FGIC) method was presented to revise the production planning model, and then a new quasi-optimal production plan was determined. The above steps were repeated until a practically feasible optimal plan and corresponding operating conditions of FCCU were obtained. The close-loop integrated strategy was validated by two cases, and it was indicated that the strategy was efficient in determining a practically executed optimal plan and corresponding operating conditions of FCCU.展开更多
With sustaining change of production mode,layout planning is no longer a thing built once for all.Cellular layout(CL) is becoming a hotspot in the research field of manufacturing system layout.Traditional researches o...With sustaining change of production mode,layout planning is no longer a thing built once for all.Cellular layout(CL) is becoming a hotspot in the research field of manufacturing system layout.Traditional researches on layout planning are mainly concentrating on aspects of layout arithmetic,style and evaluation,etc.Relatively seldom efforts are paid to CL and its specific problems as cell formation(CF),equipment sharing and CL analysis.Through problem analyzing of layout in cellular manufacturing system(CMS),research approach of cell formation,interactive layout and layout analysis threaded with process interconnection relationship(PIR) is proposed.Typical key technologies in CL like CF technology based on similarity analysis of part processes,interactive visual layout technology,layout evaluation technology founded on PIR analysis and algorithm of cell equipment sharing are put forward.Against the background of one enterprise which encounters problems of low utility of key equipments and disperse material logistic,an example of four-cell layout is given.The CL adjustment and analysis results show that equipment with high level of sharing degree should be disposed around the boundary of its main cell,and be near to other sharing cells as possible; process route should be centralized by all means,so equipment adjustment is to be implemented along direction that route intersection can be decreased; giving consideration to the existence of discrete cell,logistic route and its density should be centralized to cells formed.The proposed research can help improve equipment utility and material logistic efficiency of CL,and can be popularized to other application availably.展开更多
Process planning for large complicated stampings is more complicated, illegible and multiform than that for common stampings. In this paper, an intelligent master model of computer aided process planning (CAPP) for ...Process planning for large complicated stampings is more complicated, illegible and multiform than that for common stampings. In this paper, an intelligent master model of computer aided process planning (CAPP) for large complicated stampings has been developed based on knowledge based engineering (KBE) and feature technology. This innovative model consists of knowledge base (KB), process control structure (PCS), process information model (PIM), multidisciplinary design optimization (MDO), model link environment (MLE) and simulation engine (SE), to realize process planning, optimization, simulation and management integrated to complete intelligent CAPP system. In this model, KBE provides knowledge base, open architecture and knowledge reuse ability to deal with the multi-domain and multi-expression of process knowledge, and forms an integrated environment. With PIM, all the knowledge consisting of objects, constraints, cxtmricncc and decision-makings is carried by object-oriented method dynamically for knowledge-reasoning. PCS makes dynamical knowledge modified and updated timely and accordingly. MLE provides scv. cral methods to make CAPP sysmm associated and integrated. SE provides a programmable mechanism to interpret simulation course and result. Meanwhile, collaborative optimization, one method of MDO, is imported to deal with the optimization distributed for multiple purposes. All these make CAPP sysmm integrated and open to other systems, such as dic design and manufacturing system.展开更多
This paper introduces a system of computer aided assembly process planning for spindle box of NC lathe. The method of describing assembly information and generating assembly process drawing is presented. The principle...This paper introduces a system of computer aided assembly process planning for spindle box of NC lathe. The method of describing assembly information and generating assembly process drawing is presented. The principles of decision for assembly sequence ar展开更多
Designed as a tool for business intelligence, resource planning is used to manage the essentials of a business by integrating processes into a single system. Enterprise Resource Planning (ERP) solutions ensure all the...Designed as a tool for business intelligence, resource planning is used to manage the essentials of a business by integrating processes into a single system. Enterprise Resource Planning (ERP) solutions ensure all the organizational, operational, and procedural structures interconnection, which can be both an advantage and a disadvantage, knowing that inefficiency within one structure will lead to inefficiency in others. The originality of the approach consists in the unitary analysis of all processes which shipbuilding involves (design;evaluation of ship construction possibilities;contracting of works;contracting of supply of materials and equipment;presentation of inspections for the completed works reception;delivery of the ship into operation). The systemic approach is a notable contribution by highlighting the input and output quantities for the analyzed processes. Also, where it was found relevant, the diagrams highlight the owners of the process and show the interconnectivity of the functional departments within a shipyard. Although it is obviously the expression of in-depth knowledge of the peculiarities of Romanian shipyards, the authors hope that the work can support any shipyard that may be interested in knowing these structures (as a logical scheme mandatory to design a custom ERP software system).展开更多
Digital factory technology is an advanced manufacturing technology served as to establish a bridge between the process of product development and manufacturing.In terms of application for digital factory technology in...Digital factory technology is an advanced manufacturing technology served as to establish a bridge between the process of product development and manufacturing.In terms of application for digital factory technology in machining,especially in machining of a complicated part such as a cylinder body part,a concept of digital process planning and its framework are proposed.Its components including machining domain knowledge model,machining knowledge base,machining resource base and process planning system are studied.A machining knowledge model in tree form and an object-driven knowledge reasoning mechanism are used for machining knowledge base.The process planning system is a user interface that leads a planner to finish the planning process.A case about a cylinder head part is given to demonstrate how the platform works.The framework of digital process planning is the foundation of some intelligent CAPP systems and helps to production line planning.展开更多
The general computer-aided design (CAD) software cannot meet the mould design requirement of the autoclave process for composites, because many parameters such as temperature and pressure should be considered in the...The general computer-aided design (CAD) software cannot meet the mould design requirement of the autoclave process for composites, because many parameters such as temperature and pressure should be considered in the mould design process, in addition to the material and geometry of the part. A framed-mould computer-aided design system (FMCAD) used in the autoclave moulding process is proposed in this paper. A function model of the software is presented, in which influence factors such as part structure, mould structure, and process parameters are considered; a design model of the software is established using object oriented (O-O) technology to integrate the stiffness calculation, temperature field calculation, and deformation field calculation of mould in the design, and in the design model, a hybrid model of mould based on calculation feature and form feature is presented to support those calculations. A prototype system is developed, in which a mould design process wizard is built to integrate the input information, calculation, analysis, data storage, display, and design results of mould design. Finally, three design examples are used to verify the prototype.展开更多
Computer aided process planning system played a key role for integrating design and manufacturing or assembly systems properly considering available resources and design constraints.To take advantage of the enterprise...Computer aided process planning system played a key role for integrating design and manufacturing or assembly systems properly considering available resources and design constraints.To take advantage of the enterprise resource,the web CAPP framework was established.Case based reasoning and multi agent system were integrated in the system.The multi agent mecha- nism was discussed in the paper.And an instance of case base was introduced.They made the system run independently and contin- uously in the network environment of process planning problems.展开更多
Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative ...Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative resource planning (MECORP) are put forward.While there is Considerable pressure to improve the operation of MECORP system,their inherent complexity can make modelling a MECORP system a difficult task.Yet there could be considerable benefits in designing MECORP taking into account the operation of the system.In order to address the central research issue of developing of a methodology that can assist a manager in making decisions by modelling the operation of MECORP system.The methodology called process-oriented deci- sion model (PODM) is presented in the paper.This uses an abstracted network to model MECORP system.The MECORP system supported by PODM,can effective optimize the manifold resource,coordinate the relationship of multiple partners and assist deci- sion.Finally,an industry excample of MECORP system is described to illustrate the application of PODM.展开更多
CAPP(Computer Aided Process Planning) has already become the bottleneck of CAD/CAM system.Present two- dimensional CAPP system which is used in the enterprise needs to be input information and data again,because it ca...CAPP(Computer Aided Process Planning) has already become the bottleneck of CAD/CAM system.Present two- dimensional CAPP system which is used in the enterprise needs to be input information and data again,because it can not draw data from CAD(Computer Aided Design) model automatically after building CAD model and drawing.This has influenced extensive use of CAPP system because of its low efficiency.In this paper,three-dimensional model is built by using the parametric method, the process file cart be produced directly through drawing corresponding characteristic and parameter from the model with the aid of process database.This improves the efficiency of product development.Visual C++6.0 and SQL Server 2000 are used to devel- op WTJDCAPP prototype system based on component model and SolidWorks three-dimensional CAD platform.Engine valve-seat is taken as concrete object to validate of the technology.展开更多
Machining process data is the core of computer aided process planning application systems.It is also provides essen- tial content for product life cycle engineering.The character of CAPP that supports product LCE and ...Machining process data is the core of computer aided process planning application systems.It is also provides essen- tial content for product life cycle engineering.The character of CAPP that supports product LCE and virtual manufacturing is an- alyzed.The structure and content of machining process data concerning green manufacturing is also examined.A logic model of Machining Process Data has been built based on an object oriented approach,using UML technology and a physical model of machin- ing process data that utilizes XML technology.To realize the integration of design and process,an approach based on graph-based volume decomposition was apposed.Instead,to solve the problem of generation in the machining process,case-based reasoning and rule-based reasoning have been applied synthetically.Finally,the integration framework and interface that deal with the CAPP integration with CAD,CAM,PDM,and ERP are discussed.展开更多
Digital factory technology is a research focus in academe and industry,which is an advanced manufacturing tech- nology that is proposed to bridge product development and manufacturing.For applying digital factory tech...Digital factory technology is a research focus in academe and industry,which is an advanced manufacturing tech- nology that is proposed to bridge product development and manufacturing.For applying digital factory technology in machining domain,a concept of digital process planning and its framework are suggested,its components including machining domain knowledge model,machining knowledge base,machining resource base and process planning system are studied.The framework of digital process planning is of value for implementing digital factory technology in machining industry.展开更多
A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was ...A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was shown to be a viable alternative to hierarchical systems providing real time response to shop floor condition. An outline was done to show how to structure a distributed process plan and how its management may be achieved among manufacturers of parts that form a product. Communication between the agents involved in a distributed process planning was also shown to be important, with the controlling agent having an overall supervision of the plans. Based on the reference model a software tool was developed to realize it.展开更多
Poor plans of design project are often caused by the difficulties in realizing the underlying complexities and immeasurable characteristics in the deisgn process. To overcome this diffculty, a metric approach based on...Poor plans of design project are often caused by the difficulties in realizing the underlying complexities and immeasurable characteristics in the deisgn process. To overcome this diffculty, a metric approach based on the tasks analysis model of task importance degree was proposed. The model suggests that importance of a task can be measured through the influence to the project incurred by the imaginary failure of the task, which can be measured through three parts: the critical degree of a task to the whole project, the direct cost by the failure of a task, and the indirect cost on the other tasks affected by the failure of the task. The Analytic Hierarchy Process approach was applied to determine the critical degree and Case based Reasoning idea was used in detecting the implied error in the task. As an application case, a review work planning was given and some conclusions were arrived at.展开更多
文摘Climate change vulnerability assessment is an essential tool for identifying regions that are most susceptible to the impacts of climate change and designing effective adaptation actions that can reduce vulnerability and enhance long-term resilience of these regions.This study explored a framework for climate change vulnerability assessment in the new urban planning process in Jangwani Ward,Tanzania.Specifically,taking flood as an example,this study highlighted the steps and methods for climate change vulnerability assessment in the new urban planning process.In the study area,95 households were selected and interviewed through purposeful sampling.Additionally,10 respondents(4 females and 6 males)were interviewed for Focus Group Discussion(FGD),and 3 respondents(1 female and 2 males)were selected for Key Informant Interviews(KII)at the Ministry of Lands,Housing and Human Settlements Development.This study indicated that climate change vulnerability assessment framework involves the assessment of climatic hazards,risk elements,and adaptive capacity,and the determination of vulnerability levels.The average hazard risk rating of flood was 2.3.Socioeconomic and livelihood activities and physical infrastructures both had the average risk element rating of 3.0,and ecosystems had the average risk element rating of 2.9.Adaptive capacity ratings of knowledge,technology,economy or finance,and institution were 1.6,1.9,1.4,and 2.2,respectively.The vulnerability levels of socioeconomic and livelihood activities and physical infrastructure were very high(4.0).Ecosystems had a high vulnerability level(3.8)to flood.The very high vulnerability level of socioeconomic and livelihood activities was driven by high exposure and sensitivity to risk elements and low adaptive capacity.The study recommends adoption of the new urban planning process including preparation,planning,implementation,and monitoring-evaluation-review phases that integrates climate change vulnerability assessment in all phases.
基金National Natural Science Foundation of China (No.40606018)
文摘Computer-aided block assembly process planning based on rule-reasoning are developed in order to improve the assembly efficiency and implement the automated block assembly process planning generation in shipbuilding. First, weighted directed liaison graph (WDLG) is proposed to represent the model of block assembly process according to the characteristics of assembly relation, and edge list (EL) is used to describe assembly sequences. Shapes and assembly attributes of block parts are analyzed to determine the assembly position and matched parts of parts used frequently. Then, a series of assembly rules are generalized, and assembly sequences for block are obtained by means of rule reasoning. Final, a prototype system of computer-aided block assembly process planning is built. The system has been tested on actual block, and the results were found to be quite efficiency. Meanwhile, the fundament for the automation of block assembly process generation and integration with other systems is established.
基金supported by National Natural Science Foundation of China (Grant No. 50805009)The Eleventh Five Year Plan Defense Pre-Research Fund, China (Grant No. 51318010205)
文摘Assembly process planning(APP) for complicated products is a time-consuming and difficult work with conventional method. Virtual assembly process planning(VAPP) provides engineers a new and efficiency way. Previous studies in VAPP are almost isolated and dispersive, and have not established a whole understanding and discussed key realization techniques of VAPP from a systemic and integrated view. The integrated virtual assembly process planning(IVAPP) system is a new virtual reality based engineering application, which offers engineers an efficient, intuitive, immersive and integrated method for assembly process planning in a virtual environment. Based on analysis the information integration requirement of VAPP, the architecture of IVAPP is proposed. Through the integrated structure, IVAPP system can realize information integration and workflow controlling. In order to mode/the assembly process in IVAPP, a hierarchical assembly task list(HATL) is presented, in which different assembly tasks for assembling different components are organized into a hierarchical list. A process-oriented automatic geometrical constraint recognition algorithm(AGCR) is proposed, so that geometrical constraints between components can be automatically recognized during the process of interactive assembling. At the same time, a progressive hierarchical reasoning(PHR) model is discussed. AGCR and PHR will greatly reduce the interactive workload. A discrete control node model(DCNM) for cable harness assembly planning in IVAPP is detailed. DCNM converts a cable harness into continuous flexed line segments connected by a series of section center points, and designs can realize cable harness planning through controlling those control nodes. Mechanical assemblies (such as transmission case and engine of automobile) are used to illustrate the feasibility of the proposed method and algorithms. The application of IVAPP system reveals advantages over the traditional assembly process planning method in shortening the time-consumed in assembly planning and in minimizing the handling difficulty, excessive reorientation and dissimilarity of assembly operations.
基金supported in part by the National Natural Science Foundation of China(51825502,51775216)in part by the Program for Huazhong University of Science and Technology(HUST)Academic Frontier Youth Team(2017QYTD04).
文摘Intelligent process planning(PP)is one of the most important components in an intelligent manufacturing system and acts as a bridge between product designing and practical manufacturing.PP is a nondeterministic polynomial-time(NP)-hard problem and,as existing mathematical models are not formulated in linear forms,they cannot be solved well to achieve exact solutions for PP problems.This paper proposes a novel mixed-integer linear programming(MILP)mathematical model by considering the network topology structure and the OR nodes that represent a type of OR logic inside the network.Precedence relationships between operations are discussed by raising three types of precedence relationship matrices.Furthermore,the proposed model can be programmed in commonly-used mathematical programming solvers,such as CPLEX,Gurobi,and so forth,to search for optimal solutions for most open problems.To verify the effectiveness and generality of the proposed model,five groups of numerical experiments are conducted on well-known benchmarks.The results show that the proposed model can solve PP problems effectively and can obtain better solutions than those obtained by the state-ofthe-art algorithms.
文摘Space emergency launching is to send a satellite into space by using a rapid responsive solid rocket in the bounded time to implement the emergency Earth observation mission.The key and difficult points mainly include the business process construction of launching mission planning,validation of the effectiveness of the launching scheme,etc.This paper pro-poses the agile space emergency launching mission planning simulation and verification method,which systematically con-structs the overall technical framework of space emergency launching mission planning with multi-field area,multi-platform and multi-task parallel under the constraint of resource schedul-ing for the first time.It supports flexible reconstruction of mis-sion planning processes such as launching target planning,tra-jectory planning,path planning,action planning and launching time analysis,and can realize on-demand assembly of operation links under different mission scenarios and different plan condi-tions,so as to quickly modify and generate launching schemes.It supports the fast solution of rocket trajectory data and the accurate analysis of multi-point salvo time window recheck and can realize the fast conflict resolution of launching missions in the dimensions of launching position and launching window sequence.It supports lightweight scenario design,modular flexi-ble simulation,based on launching style,launching platform,launching rules,etc.,can realize the independent mapping of mission planning results to two-dimensional and three-dimen-sional visual simulation models,so as to achieve a smooth con-nection between mission planning and simulation.
文摘Flexible transfer line(FTL)is now widely used in ma ny manufacturing domains to realize efficiently,high quantity and economic prod uction.These manufacturing domains include automobile,tractor,internal-combu stion engine,and so on.In today’s competitive business environment,it is vit ally important for machine tool manufacturers to design flexible transfer line m ore effectively and efficiently according to a wider variety of customer demand s.This paper proposes an approach to a bidding-based flexible transfer line sc hematic design system.By analyzing manual FTL design process,the architecture o f flexible transfer line schematic design system(FTLSDS)is established.The syst em consists:of four processes:part feature modeling,process planning,FTL fac i lity layout and FTL evaluation. For FTL schematic design.a five-level proces s planning strategy named hierarchical process planning method is proposed.This method includes selection of manufacturing feature machining operation;part se t-up planning,feature sequencing,operation sequencing and process plan genera ting.The major decision relies on setup planning.According to the proceeding o f the hierarchical process planning,the structure of reasoning is proposed base d on blackboard.Under this paradigm,a cooperative effort between a hybrid coll ection of knowledge sources is possible.Total reasoning task can be divided int o some subtasks,and recursive-reasoning system is formed.It is convenient for process planning with step-by-step solution.Meanwhile,the blackboard is use d as the global data exchange area during all reasoning process.By using modula r technology,special purpose machine tools can be designed more efficiently and rapidly.The framework of machine modular design system to support machine requ irement design for FTL is established.By synthesizing the FTL evaluation criter ia.five evaluation criteria of flexible transfer 1ine schematic design are take n into account.An exampie is supplied to demonstrate and verify the validity an d feasibility of flexible transfer line schematic design approach.
文摘Production planning models generated by common modeling systems do not involve constraints for process operations, and a solution optimized by these models is called a quasi-optimal plan. The quasi-optimal plan cannot be executed in practice some time for no corresponding operating conditions. In order to determine a practi- cally feasible optimal plan and corresponding operating conditions of fluidized catalytic cracking unit (FCCU), a novel close-loop integrated strategy, including determination of a quasi-optimal plan, search of operating conditions of FCCU and revision of the production planning model, was proposed in this article. In the strategy, a generalized genetic algorithm (GA) coupled with a sequential process simulator of FCCU was applied to search operating conditions implementing the quasi-optimal plan of FCCU and output the optimal individual in the GA search as a final genetic individual. When no corresponding operating conditions were found, the final genetic individual based correction (FGIC) method was presented to revise the production planning model, and then a new quasi-optimal production plan was determined. The above steps were repeated until a practically feasible optimal plan and corresponding operating conditions of FCCU were obtained. The close-loop integrated strategy was validated by two cases, and it was indicated that the strategy was efficient in determining a practically executed optimal plan and corresponding operating conditions of FCCU.
基金supported by Defence Advanced Research Program of ChinaFoundation Research Program of Beijing Institute of Technology,China (Grant No. 20080342003)
文摘With sustaining change of production mode,layout planning is no longer a thing built once for all.Cellular layout(CL) is becoming a hotspot in the research field of manufacturing system layout.Traditional researches on layout planning are mainly concentrating on aspects of layout arithmetic,style and evaluation,etc.Relatively seldom efforts are paid to CL and its specific problems as cell formation(CF),equipment sharing and CL analysis.Through problem analyzing of layout in cellular manufacturing system(CMS),research approach of cell formation,interactive layout and layout analysis threaded with process interconnection relationship(PIR) is proposed.Typical key technologies in CL like CF technology based on similarity analysis of part processes,interactive visual layout technology,layout evaluation technology founded on PIR analysis and algorithm of cell equipment sharing are put forward.Against the background of one enterprise which encounters problems of low utility of key equipments and disperse material logistic,an example of four-cell layout is given.The CL adjustment and analysis results show that equipment with high level of sharing degree should be disposed around the boundary of its main cell,and be near to other sharing cells as possible; process route should be centralized by all means,so equipment adjustment is to be implemented along direction that route intersection can be decreased; giving consideration to the existence of discrete cell,logistic route and its density should be centralized to cells formed.The proposed research can help improve equipment utility and material logistic efficiency of CL,and can be popularized to other application availably.
文摘Process planning for large complicated stampings is more complicated, illegible and multiform than that for common stampings. In this paper, an intelligent master model of computer aided process planning (CAPP) for large complicated stampings has been developed based on knowledge based engineering (KBE) and feature technology. This innovative model consists of knowledge base (KB), process control structure (PCS), process information model (PIM), multidisciplinary design optimization (MDO), model link environment (MLE) and simulation engine (SE), to realize process planning, optimization, simulation and management integrated to complete intelligent CAPP system. In this model, KBE provides knowledge base, open architecture and knowledge reuse ability to deal with the multi-domain and multi-expression of process knowledge, and forms an integrated environment. With PIM, all the knowledge consisting of objects, constraints, cxtmricncc and decision-makings is carried by object-oriented method dynamically for knowledge-reasoning. PCS makes dynamical knowledge modified and updated timely and accordingly. MLE provides scv. cral methods to make CAPP sysmm associated and integrated. SE provides a programmable mechanism to interpret simulation course and result. Meanwhile, collaborative optimization, one method of MDO, is imported to deal with the optimization distributed for multiple purposes. All these make CAPP sysmm integrated and open to other systems, such as dic design and manufacturing system.
文摘This paper introduces a system of computer aided assembly process planning for spindle box of NC lathe. The method of describing assembly information and generating assembly process drawing is presented. The principles of decision for assembly sequence ar
文摘Designed as a tool for business intelligence, resource planning is used to manage the essentials of a business by integrating processes into a single system. Enterprise Resource Planning (ERP) solutions ensure all the organizational, operational, and procedural structures interconnection, which can be both an advantage and a disadvantage, knowing that inefficiency within one structure will lead to inefficiency in others. The originality of the approach consists in the unitary analysis of all processes which shipbuilding involves (design;evaluation of ship construction possibilities;contracting of works;contracting of supply of materials and equipment;presentation of inspections for the completed works reception;delivery of the ship into operation). The systemic approach is a notable contribution by highlighting the input and output quantities for the analyzed processes. Also, where it was found relevant, the diagrams highlight the owners of the process and show the interconnectivity of the functional departments within a shipyard. Although it is obviously the expression of in-depth knowledge of the peculiarities of Romanian shipyards, the authors hope that the work can support any shipyard that may be interested in knowing these structures (as a logical scheme mandatory to design a custom ERP software system).
文摘Digital factory technology is an advanced manufacturing technology served as to establish a bridge between the process of product development and manufacturing.In terms of application for digital factory technology in machining,especially in machining of a complicated part such as a cylinder body part,a concept of digital process planning and its framework are proposed.Its components including machining domain knowledge model,machining knowledge base,machining resource base and process planning system are studied.A machining knowledge model in tree form and an object-driven knowledge reasoning mechanism are used for machining knowledge base.The process planning system is a user interface that leads a planner to finish the planning process.A case about a cylinder head part is given to demonstrate how the platform works.The framework of digital process planning is the foundation of some intelligent CAPP systems and helps to production line planning.
文摘The general computer-aided design (CAD) software cannot meet the mould design requirement of the autoclave process for composites, because many parameters such as temperature and pressure should be considered in the mould design process, in addition to the material and geometry of the part. A framed-mould computer-aided design system (FMCAD) used in the autoclave moulding process is proposed in this paper. A function model of the software is presented, in which influence factors such as part structure, mould structure, and process parameters are considered; a design model of the software is established using object oriented (O-O) technology to integrate the stiffness calculation, temperature field calculation, and deformation field calculation of mould in the design, and in the design model, a hybrid model of mould based on calculation feature and form feature is presented to support those calculations. A prototype system is developed, in which a mould design process wizard is built to integrate the input information, calculation, analysis, data storage, display, and design results of mould design. Finally, three design examples are used to verify the prototype.
文摘Computer aided process planning system played a key role for integrating design and manufacturing or assembly systems properly considering available resources and design constraints.To take advantage of the enterprise resource,the web CAPP framework was established.Case based reasoning and multi agent system were integrated in the system.The multi agent mecha- nism was discussed in the paper.And an instance of case base was introduced.They made the system run independently and contin- uously in the network environment of process planning problems.
文摘Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative resource planning (MECORP) are put forward.While there is Considerable pressure to improve the operation of MECORP system,their inherent complexity can make modelling a MECORP system a difficult task.Yet there could be considerable benefits in designing MECORP taking into account the operation of the system.In order to address the central research issue of developing of a methodology that can assist a manager in making decisions by modelling the operation of MECORP system.The methodology called process-oriented deci- sion model (PODM) is presented in the paper.This uses an abstracted network to model MECORP system.The MECORP system supported by PODM,can effective optimize the manifold resource,coordinate the relationship of multiple partners and assist deci- sion.Finally,an industry excample of MECORP system is described to illustrate the application of PODM.
文摘CAPP(Computer Aided Process Planning) has already become the bottleneck of CAD/CAM system.Present two- dimensional CAPP system which is used in the enterprise needs to be input information and data again,because it can not draw data from CAD(Computer Aided Design) model automatically after building CAD model and drawing.This has influenced extensive use of CAPP system because of its low efficiency.In this paper,three-dimensional model is built by using the parametric method, the process file cart be produced directly through drawing corresponding characteristic and parameter from the model with the aid of process database.This improves the efficiency of product development.Visual C++6.0 and SQL Server 2000 are used to devel- op WTJDCAPP prototype system based on component model and SolidWorks three-dimensional CAD platform.Engine valve-seat is taken as concrete object to validate of the technology.
文摘Machining process data is the core of computer aided process planning application systems.It is also provides essen- tial content for product life cycle engineering.The character of CAPP that supports product LCE and virtual manufacturing is an- alyzed.The structure and content of machining process data concerning green manufacturing is also examined.A logic model of Machining Process Data has been built based on an object oriented approach,using UML technology and a physical model of machin- ing process data that utilizes XML technology.To realize the integration of design and process,an approach based on graph-based volume decomposition was apposed.Instead,to solve the problem of generation in the machining process,case-based reasoning and rule-based reasoning have been applied synthetically.Finally,the integration framework and interface that deal with the CAPP integration with CAD,CAM,PDM,and ERP are discussed.
文摘Digital factory technology is a research focus in academe and industry,which is an advanced manufacturing tech- nology that is proposed to bridge product development and manufacturing.For applying digital factory technology in machining domain,a concept of digital process planning and its framework are suggested,its components including machining domain knowledge model,machining knowledge base,machining resource base and process planning system are studied.The framework of digital process planning is of value for implementing digital factory technology in machining industry.
文摘A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was shown to be a viable alternative to hierarchical systems providing real time response to shop floor condition. An outline was done to show how to structure a distributed process plan and how its management may be achieved among manufacturers of parts that form a product. Communication between the agents involved in a distributed process planning was also shown to be important, with the controlling agent having an overall supervision of the plans. Based on the reference model a software tool was developed to realize it.
文摘Poor plans of design project are often caused by the difficulties in realizing the underlying complexities and immeasurable characteristics in the deisgn process. To overcome this diffculty, a metric approach based on the tasks analysis model of task importance degree was proposed. The model suggests that importance of a task can be measured through the influence to the project incurred by the imaginary failure of the task, which can be measured through three parts: the critical degree of a task to the whole project, the direct cost by the failure of a task, and the indirect cost on the other tasks affected by the failure of the task. The Analytic Hierarchy Process approach was applied to determine the critical degree and Case based Reasoning idea was used in detecting the implied error in the task. As an application case, a review work planning was given and some conclusions were arrived at.