Water pollution control planning for the Taizi River watershed,a typical Chinese case study,is presented in this paper. Based on comprehensive analysis.water quality in the watershed was assessed and predicated;water ...Water pollution control planning for the Taizi River watershed,a typical Chinese case study,is presented in this paper. Based on comprehensive analysis.water quality in the watershed was assessed and predicated;water quality models for the river and reservoir were built;and function of water bodies and environmental assimilative capacity were determined ;and then the planning for industrial pollution sources and concentrated sewage treatment were made respectively.展开更多
Manufacturing system, with high level of complexity and with a mix of semi-repetitive and repetitive products, to become productive, should seek the standardization of products and processes to obtain the optimization...Manufacturing system, with high level of complexity and with a mix of semi-repetitive and repetitive products, to become productive, should seek the standardization of products and processes to obtain the optimization of use of production resources. However, it is necessary to measure the productivity, so that the system of measurement and control of manufacturing processes are an element critical as to ensure greater visibility of the flow's restrictions, minimized when detected properly. In this case, the automation of factory's measurement process can effectively contribute to ensuring the effectiveness of the function control of a manufacturing system. It is important to consider that the automation of the system of measurement and control of manufacturing processes, of complex environment, is heavily dependent of IT tools applied directly in the interface computational between the operation systems and the corporate systems. This heavy reliance, if exploited technically properly, allows that automation of the system of measurement and control of production makes the access to time real of availability of manufacturing process's data, such as processing time and setup time that it can export to a specialist software in programming production, for example, feasible. In this paper, the automation of the system of measurement and control of production is approached, in order to identify the main possibilities of the design of an information system capable to integrate the flow of information in an environment internal on manufacturing organizations, with emphasis in the digital manufacturing paradigm.展开更多
It is vital for pipeline assembly enterprise to respond to changing market needs quickly and keep its cost advantage. A production planning and control (PPC) model under supply chain management combining with operat...It is vital for pipeline assembly enterprise to respond to changing market needs quickly and keep its cost advantage. A production planning and control (PPC) model under supply chain management combining with operation characteristics of pipeline assembly enterprise was proposed. The present model can realize synchroni- zation in real-time response in production by establishing a win-win corporate model, classified regulation be- tween strategic parts and non-strategic parts, postponing the production of special modules and guaranteeing pro- duction at the bottleneck.展开更多
This paper introduced domestic and overseas status, the historical evolution and the development history of earthquake disaster reduction planning. The urgencies and realistic significance were analyzed to carry out e...This paper introduced domestic and overseas status, the historical evolution and the development history of earthquake disaster reduction planning. The urgencies and realistic significance were analyzed to carry out earthquake disaster reduction planning for districts or countries in the northwest. With Hongsibao District in Wuzhong City, Ningxia Province as an example, this article analyzed in detail the present situation and the special problems of earthquake disaster reduction planning in Northwest China. The relevant solving measures were put forward in order to offer a reference for the scientific establishment and effective implementation of earth- quake disaster reduction planning in Northwest China. The foundation of earthquake disaster reduction in the Hongsibao District is still very weak, there is a single earthquake monitoring means, the emergency rescue system is not complete, the working mechanism is not perfect, and the lack of funding for the work of earthquake disaster reduction.展开更多
The plan view pattern control theoretical models were simplified. Under the condition of constant volume for the plan view pattern compensation, the relation between the thickness and the length can be simplified to t...The plan view pattern control theoretical models were simplified. Under the condition of constant volume for the plan view pattern compensation, the relation between the thickness and the length can be simplified to the linearity in the segment for the plan view pattern control function. The compensation volume can be dispersed for easy calculation. By comparing the model calculation result with the actual result, it was concluded that the simplified model can be used for the online control process.展开更多
Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC ( plan view pattern control) on width accuracy of plate mill. The thickness correction calculation f...Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC ( plan view pattern control) on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.展开更多
The forward slip model with adhesion was used to derive the formula of calculating taper rolling time. The relation between the rolling time and the taper length and the relation between the rolling time and the taper...The forward slip model with adhesion was used to derive the formula of calculating taper rolling time. The relation between the rolling time and the taper length and the relation between the rolling time and the taper thickness can be obtained. The numerical solution for this formula was used on site. According to the simulation result, the roll gap value should be changed linearly with rolling time.展开更多
The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method(GPM) and direct shooting method(DSM...The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method(GPM) and direct shooting method(DSM) is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.展开更多
Several fuel plants that supply nuclear research reactors need to increase their production capacity in order to meet the growing demand for this kind of nuclear fuel. After the enlargement of the production capacity ...Several fuel plants that supply nuclear research reactors need to increase their production capacity in order to meet the growing demand for this kind of nuclear fuel. After the enlargement of the production capacity of such plants, there will be the need of managing the new production level. That level is usually the industrial one, which poses challenges to the managerial staff. Such challenges come from the fact that several of those plants operate today on a laboratorial basis and do not carry inventory. The change to the industrial production pace asks for new actions regarding planning and control. The production process based on the hydrolysis of UF6 is not a frequent production route for nuclear fuel. Production planning and control of the industrial level of fuel production on that production route is a new field of studies. The approach of the paper consists in the creation of a mathematical linear model for minimization of costs. We also carried out a sensitivity analysis of the model. The results help in minimizing costs in different production schemes and show the need of inventory. The mathematical model is dynamic, so that it issues better results if performed monthly. The management team will therefore have a clearer view of the costs and of the new, necessary production and inventory levels.展开更多
In order to deal with global climate warming and practice the construction of national ecological civilization,a sponge city has become an important national plan for regional comprehensive management and development ...In order to deal with global climate warming and practice the construction of national ecological civilization,a sponge city has become an important national plan for regional comprehensive management and development because it can systematically solve the issues of regional water resources,water security,water environment and water ecology,and provide a comprehensive plan of sustainable development for regional water control,storage and use.Sponge city construction has been carried out across the country.In this paper,taking Dalang Town as an example,and combining its local climate,geological geomorphology,hydrological conditions,current situation and future planning of urban space,management system and other characteristics,the connotation,construction strategy and objectives,index decomposition and other key contents of sponge city were discussed,and the methods of sponge city construction in the builtup area with high rainfall,abundant groundwater and high density were studied to provide reference for formulating solutions and schemes for Dalang Town and developing sponge city construction in the Pearl River Delta.展开更多
Cable-driven parallel robots(CDPRs) are categorized as a type of parallel manipulators. In CDPRs, flexible cables are used to take the place of rigid links. The particular property of cables provides CDPRs several adv...Cable-driven parallel robots(CDPRs) are categorized as a type of parallel manipulators. In CDPRs, flexible cables are used to take the place of rigid links. The particular property of cables provides CDPRs several advantages, including larger workspaces, higher payload-to-weight ratio and lower manufacturing costs rather than rigid-link robots. In this paper, the history of the development of CDPRs is introduced and several successful latest application cases of CDPRs are presented. The theory development of CDPRs is introduced focusing on design, performance analysis and control theory. Research on CDPRs gains wide attention and is highly motivated by the modern engineering demand for large load capacity and workspace. A number of exciting advances in CDPRs are summarized in this paper since it is proposed in the 1980 s, which points to a fruitful future both in theory and application. In order to meet the increasing requirements of robot in different areas, future steps foresee more in-depth research and extension applications of CDPRs including intelligent control, composite materials, integrated and reconfigurable design.展开更多
This paper presents a computationally efficient real-time trajectory planning framework for typical unmanned combat aerial vehicle (UCAV) performing autonomous air-to-surface (A/S) attack. It combines the benefits...This paper presents a computationally efficient real-time trajectory planning framework for typical unmanned combat aerial vehicle (UCAV) performing autonomous air-to-surface (A/S) attack. It combines the benefits of inverse dynamics optimization method and receding horizon optimal control technique. Firstly, the ground attack trajectory planning problem is mathematically formulated as a receding horizon optimal control problem (RHC-OCP). In particular, an approximate elliptic launch acceptable region (LAR) model is proposed to model the critical weapon delivery constraints. Secondly, a planning algorithm based on inverse dynamics optimization, which has high computational efficiency and good convergence properties, is developed to solve the RHCOCP in real-time. Thirdly, in order to improve robustness and adaptivity in a dynamic and uncer- tain environment, a two-degree-of-freedom (2-DOF) receding horizon control architecture is introduced and a regular real-time update strategy is proposed as well, and the real-time feedback can be achieved and the not-converged situations can be handled. Finally, numerical simulations demon- strate the efficiency of this framework, and the results also show that the presented technique is well suited for real-time implementation in dynamic and uncertain environment.展开更多
Vehicle collision avoidance system is a kind of auxiliary driving system based on vehicle active safety,which can assist the driver to take the initiative to avoid obstacles under certain conditions,so as to effective...Vehicle collision avoidance system is a kind of auxiliary driving system based on vehicle active safety,which can assist the driver to take the initiative to avoid obstacles under certain conditions,so as to effectively improve the driving safety of vehicle.This paper presents a collision avoidance system for an autonomous vehicle based on an active front steering,which mainly consists of a path planner and a robust tracking controller.A path planner is designed based on polynomial parameterization optimized by simulated annealing algorithm,which plans an evasive trajectory to bypass the obstacle and avoid crashes.The dynamic models of the AFS system,vehicle as well as the driver model are established,and based on these,a robust tracking controller is proposed,which controls the system to resist external disturbances and work in accordance with the planning trajectory.The proposed collision avoidance system is testified through CarSim and Simulink combined simulation platform.The simulation results show that it can effectively track the planning trajectory,and improve the steering stability and anti-interference performance of the vehicle.展开更多
This paper aims to develop a conceptual framework for real-time production planning and control(PPC).Firstly,we discuss the most prominently applied contemporary information and communication technologies for PPC.En...This paper aims to develop a conceptual framework for real-time production planning and control(PPC).Firstly,we discuss the most prominently applied contemporary information and communication technologies for PPC.Enterprise resource planning(ERP) systems that integrate the value chain in an enterprise,manufacturing execution systems that manage and control the production on shopfloor,and advanced planning and scheduling(APS)systems that develop solutions for complex planning problems are the planning and control systems that have been analyzed.We emphasize the application of radio frequency identification as the most advanced and promising emerging real-time data capture technology that is currently available to manufacturers.Having analyzed the features and shortcomings of the individual systems perse,and by considering the advantages that may be realized through effective integration of these otherwise discrete systems,we propose a framework for real-time PPC.展开更多
As more and more composite materials are used in lightweight vehicle white bodies,self-pierce riveting(SPR)technology has attracted great attention.However,the existing riveting tools still have the disadvantages of l...As more and more composite materials are used in lightweight vehicle white bodies,self-pierce riveting(SPR)technology has attracted great attention.However,the existing riveting tools still have the disadvantages of low efficiency and flexibility.To improve these disadvantages and the riveting qualification rate,this paper improves the control scheme of the existing riveting tools,and proposes a novel controller design approach of the flexible servo riveting system based on the RBF network and SPR process.Firstly,this paper briefly introduces the working principle and SPR procedure of the servo riveting tool.Then a moving component force analysis is performed,which lays the foundation for the motion control.Secondly,the riveting quality inspection rules of traditional riveting tools are used for reference to plan the force-displacement curve autonomously.To control this process,the riveting force is fed back into the closed-loop control of the riveting tool and the riveting speed is computed based on the admittance control algorithm.Then,this paper adopts the permanent magnet synchronous motor(PMSM)as the power of riveting tool,and proposes an integral sliding mode control approach based on the improved reaching law and the radial basis function(RBF)network friction compensation for the PMSM speed control.Finally,the proposed control approach is simulated by Matlab,and is applied to the servo riveting system designed by our laboratory.The simulation and riveting results show the feasibility of the designed controller.展开更多
The autonomous vehicles are the future of mobility across the globe and are expected to touch the lives of every person of all ages. But this comes with certain challenges regarding safety, reliability, cost, legal fr...The autonomous vehicles are the future of mobility across the globe and are expected to touch the lives of every person of all ages. But this comes with certain challenges regarding safety, reliability, cost, legal framework, regulations, etc. however, of all the concern safety and reliability are of utmost importance for researchers and engineers. The current research is focused on the movement of the autonomous vehicle in the work zone. The work zone is one of the most challenging areas for the autonomous vehicle to drive from. This is because the work zones are very dynamic, and all the construction activities are specific to the site condition and cannot always be predefined. The study provides a concept of how pavement marking can be used for smooth <span style="font-family:Verdana;">movement through the complicated work zone. In this study, various pav</span><span style="font-family:Verdana;">ement marking signs have been designed as a concept considering the standard colors and striping width being used in the Manual of Uniform Traffic control device (MUTCD). The study assumes that the movement of the autonomous vehicle will not be exclusive and that it will move with the driver driven vehicle. It is expected that autonomous vehicles will require special pavement marking and signage for smooth movement through the work zone. These pavement marking and signage will eventually become part of standard Traffic Control Plans (TCP) and Maintenance of Traffic Plans (MOT). The research aims to study the current research being done in this area and technology being used for detecting various pavement markings and signages.</span>展开更多
In the process of urban development in China,the vast majority of urban construction is faced with the prominent contradiction between scarce land resources and vigorous construction demand.Moreover,high-density and h...In the process of urban development in China,the vast majority of urban construction is faced with the prominent contradiction between scarce land resources and vigorous construction demand.Moreover,high-density and high-intensity development is ubiquitous.However,the overall development amount of a city is restricted by the bearing capacity of road network to some extent,and there is an upper limit.Based on this,Xingtang County of Shijiazhuang City is taken as the research object,and bearing capacity of road network is selected as research emphasis.With the aid of traffi c planning software TransCAD,simulation and quantitative analysis are conducted,and traffi c demand is forecasted,to analyze impact relationship between land-use planning and traffic planning in regulatory planning.It facilitates later modifi cation and optimization of volume rate in the land development intensity index,thus providing rational basis for programme adjustment,preparation and management of regulatory planning in Xingtang County.展开更多
On the basis of the practice in Guangzhou in recent years,this article proposes the tech-nique of the“control”approach in city planning,and presents its specific application and ex-plorations with the example of the...On the basis of the practice in Guangzhou in recent years,this article proposes the tech-nique of the“control”approach in city planning,and presents its specific application and ex-plorations with the example of the planning for the developing area of Chigang inGuangzhou.With the reform of the urban economic-political system and the advancement of theopen-door policy,significant changes are evolving in the ideas and the ways of city planningand design.To meet the demand of these developments,the new“control”approach in cityplanning and design is thus adopted.展开更多
Since 1980s,with the further reform of political and economic systems,the urban construc-tion in our country has undergone great changes,greater than ever.Such changes pose a series ofnew problems to urban planning:Ho...Since 1980s,with the further reform of political and economic systems,the urban construc-tion in our country has undergone great changes,greater than ever.Such changes pose a series ofnew problems to urban planning:How should planning be suitable for the development of moderncities?How should planning management coordinate with urban planning?How to carry out ur-ban planning under new situations? etc.The answers to these problems lie in one point:urbanplanning and plann ing management must be restructured.Only when the former is well com-bined with the latter can the above problems be solved satisfactorily.This article provides someviews in this respect.展开更多
THIS year, Women of China asked two 30-year-old women from the Yimeng mountain area in Shandong Province about their chosen methods of birth control. Both women reported using intrauterine devices (IUDs), which they h...THIS year, Women of China asked two 30-year-old women from the Yimeng mountain area in Shandong Province about their chosen methods of birth control. Both women reported using intrauterine devices (IUDs), which they had placed by local gynecologists at the hospital 40 days after giving birth. Are these women aware of other contraceptive methods? Some rural women tell us they know of other methods such as oral contraception, contraceptive implants and tubal ligation.展开更多
文摘Water pollution control planning for the Taizi River watershed,a typical Chinese case study,is presented in this paper. Based on comprehensive analysis.water quality in the watershed was assessed and predicated;water quality models for the river and reservoir were built;and function of water bodies and environmental assimilative capacity were determined ;and then the planning for industrial pollution sources and concentrated sewage treatment were made respectively.
文摘Manufacturing system, with high level of complexity and with a mix of semi-repetitive and repetitive products, to become productive, should seek the standardization of products and processes to obtain the optimization of use of production resources. However, it is necessary to measure the productivity, so that the system of measurement and control of manufacturing processes are an element critical as to ensure greater visibility of the flow's restrictions, minimized when detected properly. In this case, the automation of factory's measurement process can effectively contribute to ensuring the effectiveness of the function control of a manufacturing system. It is important to consider that the automation of the system of measurement and control of manufacturing processes, of complex environment, is heavily dependent of IT tools applied directly in the interface computational between the operation systems and the corporate systems. This heavy reliance, if exploited technically properly, allows that automation of the system of measurement and control of production makes the access to time real of availability of manufacturing process's data, such as processing time and setup time that it can export to a specialist software in programming production, for example, feasible. In this paper, the automation of the system of measurement and control of production is approached, in order to identify the main possibilities of the design of an information system capable to integrate the flow of information in an environment internal on manufacturing organizations, with emphasis in the digital manufacturing paradigm.
文摘It is vital for pipeline assembly enterprise to respond to changing market needs quickly and keep its cost advantage. A production planning and control (PPC) model under supply chain management combining with operation characteristics of pipeline assembly enterprise was proposed. The present model can realize synchroni- zation in real-time response in production by establishing a win-win corporate model, classified regulation be- tween strategic parts and non-strategic parts, postponing the production of special modules and guaranteeing pro- duction at the bottleneck.
基金Supported by State Key Laboratory of Loess and Quaternary Geology Open-end Fund(SKLLQG1426)Post-doctoral Foundation and National Natural Science Foundation of China(41102107)~~
文摘This paper introduced domestic and overseas status, the historical evolution and the development history of earthquake disaster reduction planning. The urgencies and realistic significance were analyzed to carry out earthquake disaster reduction planning for districts or countries in the northwest. With Hongsibao District in Wuzhong City, Ningxia Province as an example, this article analyzed in detail the present situation and the special problems of earthquake disaster reduction planning in Northwest China. The relevant solving measures were put forward in order to offer a reference for the scientific establishment and effective implementation of earth- quake disaster reduction planning in Northwest China. The foundation of earthquake disaster reduction in the Hongsibao District is still very weak, there is a single earthquake monitoring means, the emergency rescue system is not complete, the working mechanism is not perfect, and the lack of funding for the work of earthquake disaster reduction.
基金Item Sponsored by National Economy Trade Committee Foundation(ZZ0113A040201)
文摘The plan view pattern control theoretical models were simplified. Under the condition of constant volume for the plan view pattern compensation, the relation between the thickness and the length can be simplified to the linearity in the segment for the plan view pattern control function. The compensation volume can be dispersed for easy calculation. By comparing the model calculation result with the actual result, it was concluded that the simplified model can be used for the online control process.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.N120407007)
文摘Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC ( plan view pattern control) on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.
基金Item Sponsored by National Economy Trade Committee Foundation (ZZ0113A040201)
文摘The forward slip model with adhesion was used to derive the formula of calculating taper rolling time. The relation between the rolling time and the taper length and the relation between the rolling time and the taper thickness can be obtained. The numerical solution for this formula was used on site. According to the simulation result, the roll gap value should be changed linearly with rolling time.
基金supported by the National Natural Science Foundation of China (11472058)
文摘The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method(GPM) and direct shooting method(DSM) is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.
文摘Several fuel plants that supply nuclear research reactors need to increase their production capacity in order to meet the growing demand for this kind of nuclear fuel. After the enlargement of the production capacity of such plants, there will be the need of managing the new production level. That level is usually the industrial one, which poses challenges to the managerial staff. Such challenges come from the fact that several of those plants operate today on a laboratorial basis and do not carry inventory. The change to the industrial production pace asks for new actions regarding planning and control. The production process based on the hydrolysis of UF6 is not a frequent production route for nuclear fuel. Production planning and control of the industrial level of fuel production on that production route is a new field of studies. The approach of the paper consists in the creation of a mathematical linear model for minimization of costs. We also carried out a sensitivity analysis of the model. The results help in minimizing costs in different production schemes and show the need of inventory. The mathematical model is dynamic, so that it issues better results if performed monthly. The management team will therefore have a clearer view of the costs and of the new, necessary production and inventory levels.
文摘In order to deal with global climate warming and practice the construction of national ecological civilization,a sponge city has become an important national plan for regional comprehensive management and development because it can systematically solve the issues of regional water resources,water security,water environment and water ecology,and provide a comprehensive plan of sustainable development for regional water control,storage and use.Sponge city construction has been carried out across the country.In this paper,taking Dalang Town as an example,and combining its local climate,geological geomorphology,hydrological conditions,current situation and future planning of urban space,management system and other characteristics,the connotation,construction strategy and objectives,index decomposition and other key contents of sponge city were discussed,and the methods of sponge city construction in the builtup area with high rainfall,abundant groundwater and high density were studied to provide reference for formulating solutions and schemes for Dalang Town and developing sponge city construction in the Pearl River Delta.
基金Supported by National Natural Science Foundation of China(Grant Nos.51605126,51575150,91748109)
文摘Cable-driven parallel robots(CDPRs) are categorized as a type of parallel manipulators. In CDPRs, flexible cables are used to take the place of rigid links. The particular property of cables provides CDPRs several advantages, including larger workspaces, higher payload-to-weight ratio and lower manufacturing costs rather than rigid-link robots. In this paper, the history of the development of CDPRs is introduced and several successful latest application cases of CDPRs are presented. The theory development of CDPRs is introduced focusing on design, performance analysis and control theory. Research on CDPRs gains wide attention and is highly motivated by the modern engineering demand for large load capacity and workspace. A number of exciting advances in CDPRs are summarized in this paper since it is proposed in the 1980 s, which points to a fruitful future both in theory and application. In order to meet the increasing requirements of robot in different areas, future steps foresee more in-depth research and extension applications of CDPRs including intelligent control, composite materials, integrated and reconfigurable design.
基金supported by the National Defense Foundation of China(No.403060103)
文摘This paper presents a computationally efficient real-time trajectory planning framework for typical unmanned combat aerial vehicle (UCAV) performing autonomous air-to-surface (A/S) attack. It combines the benefits of inverse dynamics optimization method and receding horizon optimal control technique. Firstly, the ground attack trajectory planning problem is mathematically formulated as a receding horizon optimal control problem (RHC-OCP). In particular, an approximate elliptic launch acceptable region (LAR) model is proposed to model the critical weapon delivery constraints. Secondly, a planning algorithm based on inverse dynamics optimization, which has high computational efficiency and good convergence properties, is developed to solve the RHCOCP in real-time. Thirdly, in order to improve robustness and adaptivity in a dynamic and uncer- tain environment, a two-degree-of-freedom (2-DOF) receding horizon control architecture is introduced and a regular real-time update strategy is proposed as well, and the real-time feedback can be achieved and the not-converged situations can be handled. Finally, numerical simulations demon- strate the efficiency of this framework, and the results also show that the presented technique is well suited for real-time implementation in dynamic and uncertain environment.
基金supported by the Research Project of Advanced Manufacture Technology for Automobile Parts(Chongqing University of Technology)Ministry of Education(Grant No.2015KLMT04)the National Natural Science Foundation of China(Grant No.51375007 and 51605219)
文摘Vehicle collision avoidance system is a kind of auxiliary driving system based on vehicle active safety,which can assist the driver to take the initiative to avoid obstacles under certain conditions,so as to effectively improve the driving safety of vehicle.This paper presents a collision avoidance system for an autonomous vehicle based on an active front steering,which mainly consists of a path planner and a robust tracking controller.A path planner is designed based on polynomial parameterization optimized by simulated annealing algorithm,which plans an evasive trajectory to bypass the obstacle and avoid crashes.The dynamic models of the AFS system,vehicle as well as the driver model are established,and based on these,a robust tracking controller is proposed,which controls the system to resist external disturbances and work in accordance with the planning trajectory.The proposed collision avoidance system is testified through CarSim and Simulink combined simulation platform.The simulation results show that it can effectively track the planning trajectory,and improve the steering stability and anti-interference performance of the vehicle.
基金support of the research program SFI NORMAN(Norwegian Manufacturing Future)
文摘This paper aims to develop a conceptual framework for real-time production planning and control(PPC).Firstly,we discuss the most prominently applied contemporary information and communication technologies for PPC.Enterprise resource planning(ERP) systems that integrate the value chain in an enterprise,manufacturing execution systems that manage and control the production on shopfloor,and advanced planning and scheduling(APS)systems that develop solutions for complex planning problems are the planning and control systems that have been analyzed.We emphasize the application of radio frequency identification as the most advanced and promising emerging real-time data capture technology that is currently available to manufacturers.Having analyzed the features and shortcomings of the individual systems perse,and by considering the advantages that may be realized through effective integration of these otherwise discrete systems,we propose a framework for real-time PPC.
基金The authors gratefully thank the research funding by the National Key Research and Development Plan of China(Grant No.2017YFB1303503)the research supported by the Key Research and Development Program of Shandong Province(Grant No.2019JZZY010441)+1 种基金the National Natural Science Foundation of China(Grant No.62103234)the project supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2021QF027).
文摘As more and more composite materials are used in lightweight vehicle white bodies,self-pierce riveting(SPR)technology has attracted great attention.However,the existing riveting tools still have the disadvantages of low efficiency and flexibility.To improve these disadvantages and the riveting qualification rate,this paper improves the control scheme of the existing riveting tools,and proposes a novel controller design approach of the flexible servo riveting system based on the RBF network and SPR process.Firstly,this paper briefly introduces the working principle and SPR procedure of the servo riveting tool.Then a moving component force analysis is performed,which lays the foundation for the motion control.Secondly,the riveting quality inspection rules of traditional riveting tools are used for reference to plan the force-displacement curve autonomously.To control this process,the riveting force is fed back into the closed-loop control of the riveting tool and the riveting speed is computed based on the admittance control algorithm.Then,this paper adopts the permanent magnet synchronous motor(PMSM)as the power of riveting tool,and proposes an integral sliding mode control approach based on the improved reaching law and the radial basis function(RBF)network friction compensation for the PMSM speed control.Finally,the proposed control approach is simulated by Matlab,and is applied to the servo riveting system designed by our laboratory.The simulation and riveting results show the feasibility of the designed controller.
文摘The autonomous vehicles are the future of mobility across the globe and are expected to touch the lives of every person of all ages. But this comes with certain challenges regarding safety, reliability, cost, legal framework, regulations, etc. however, of all the concern safety and reliability are of utmost importance for researchers and engineers. The current research is focused on the movement of the autonomous vehicle in the work zone. The work zone is one of the most challenging areas for the autonomous vehicle to drive from. This is because the work zones are very dynamic, and all the construction activities are specific to the site condition and cannot always be predefined. The study provides a concept of how pavement marking can be used for smooth <span style="font-family:Verdana;">movement through the complicated work zone. In this study, various pav</span><span style="font-family:Verdana;">ement marking signs have been designed as a concept considering the standard colors and striping width being used in the Manual of Uniform Traffic control device (MUTCD). The study assumes that the movement of the autonomous vehicle will not be exclusive and that it will move with the driver driven vehicle. It is expected that autonomous vehicles will require special pavement marking and signage for smooth movement through the work zone. These pavement marking and signage will eventually become part of standard Traffic Control Plans (TCP) and Maintenance of Traffic Plans (MOT). The research aims to study the current research being done in this area and technology being used for detecting various pavement markings and signages.</span>
文摘In the process of urban development in China,the vast majority of urban construction is faced with the prominent contradiction between scarce land resources and vigorous construction demand.Moreover,high-density and high-intensity development is ubiquitous.However,the overall development amount of a city is restricted by the bearing capacity of road network to some extent,and there is an upper limit.Based on this,Xingtang County of Shijiazhuang City is taken as the research object,and bearing capacity of road network is selected as research emphasis.With the aid of traffi c planning software TransCAD,simulation and quantitative analysis are conducted,and traffi c demand is forecasted,to analyze impact relationship between land-use planning and traffic planning in regulatory planning.It facilitates later modifi cation and optimization of volume rate in the land development intensity index,thus providing rational basis for programme adjustment,preparation and management of regulatory planning in Xingtang County.
文摘On the basis of the practice in Guangzhou in recent years,this article proposes the tech-nique of the“control”approach in city planning,and presents its specific application and ex-plorations with the example of the planning for the developing area of Chigang inGuangzhou.With the reform of the urban economic-political system and the advancement of theopen-door policy,significant changes are evolving in the ideas and the ways of city planningand design.To meet the demand of these developments,the new“control”approach in cityplanning and design is thus adopted.
文摘Since 1980s,with the further reform of political and economic systems,the urban construc-tion in our country has undergone great changes,greater than ever.Such changes pose a series ofnew problems to urban planning:How should planning be suitable for the development of moderncities?How should planning management coordinate with urban planning?How to carry out ur-ban planning under new situations? etc.The answers to these problems lie in one point:urbanplanning and plann ing management must be restructured.Only when the former is well com-bined with the latter can the above problems be solved satisfactorily.This article provides someviews in this respect.
文摘THIS year, Women of China asked two 30-year-old women from the Yimeng mountain area in Shandong Province about their chosen methods of birth control. Both women reported using intrauterine devices (IUDs), which they had placed by local gynecologists at the hospital 40 days after giving birth. Are these women aware of other contraceptive methods? Some rural women tell us they know of other methods such as oral contraception, contraceptive implants and tubal ligation.