This article investigates the dynamic characteristics of deflectable nose missiles with rotary single-channel control. After introduction of effective attack and sideslip angles as well as quasi-body coordinates based...This article investigates the dynamic characteristics of deflectable nose missiles with rotary single-channel control. After introduction of effective attack and sideslip angles as well as quasi-body coordinates based on the spin characteristics of the missile＇s body, an integrated rigid kinetic model of missile with deflectable nose control is set up in the quasi-body coordinates considering the interaction between the missile＇s nose and body by using rootless multi-rigid-body system dynamics and is linearized. Then an analysis with simulation is conducted to investigate the coupling characteristics between the channels, the influences of nose deflection on the body and the dynamic characteristics of missile＇s body. The results indicate that various channels of missiles with deflectable nose control are coupled cross-linked; the nose deflection tends to make the body move in the opposite direction and, finally, evidences the correctness and reasonability of the kinetic model proposed by this article.展开更多
A 7 degree-of-freedom （DOF） 4 wheels vehicle dynamics model based on Matlab-Simulink is established,and 7 DOF vehicle dynamics equations in the form of nonlinear state-space standards are given.The characters of the...A 7 degree-of-freedom （DOF） 4 wheels vehicle dynamics model based on Matlab-Simulink is established,and 7 DOF vehicle dynamics equations in the form of nonlinear state-space standards are given.The characters of the electronic throttle and the active braking system have been analyzed.And the electronic throttle model and the active braking system model are built according to the test results respectively.Off-line simulation results indicate that the model is suitable for the vehicle adaptive cruise control system,and both of the electronic throttle and the active braking system work in a reasonable way.An adaptive cruise control （ACC） example illustrates that the model has a good performance in cruise and distance keeping.展开更多
A first principles-based dynamic model for a continuous catalyst regeneration (CCR) platforming process, the UOP commercial naphtha catalytic reforming process, is developed in this paper. The lumping details of the n...A first principles-based dynamic model for a continuous catalyst regeneration (CCR) platforming process, the UOP commercial naphtha catalytic reforming process, is developed in this paper. The lumping details of the naphtha feed and reaction scheme of the reaction model are given. The process model is composed of the reforming reaction model with catalyst deactivation, the furnace model and the separator model, which is capable of capturing the major dynamics that occurs in this process system. Dynamic simulations are performed based on Gear numerical algorithm and method of lines (MOL), a numerical technique dealing with partial differential equations (PDEs). The results of simulation are also presented. Dynamic responses caused by disturbances in the process system can be correctly predicted through simulations.展开更多
Accurate modeling and simulation of autonomous underwater vehicle （AUV） is essential for autonomous control and maneuverability research. In this paper, a mini AUV- ＂MAUV-Ⅱ＂ was researched and the nonlinear mathe...Accurate modeling and simulation of autonomous underwater vehicle （AUV） is essential for autonomous control and maneuverability research. In this paper, a mini AUV- ＂MAUV-Ⅱ＂ was researched and the nonlinear mathematic model of the AUV in spatial motion was derived based on momentum theorem. The forces acting on AUV were resolved to several modules which were expressed in matrix form. Based on the motion model and combined with virtual reality technology, a motion simulation system was constructed. Considering the characteristic of ＂MAUV-Ⅱ ＂, the heading control and depth control were simulated by adopting S-surface control method. A long distance traveling simulation experiment based on target planning was also done. The simulation results show that the ＂MAUV-Ⅱ＂ has good spatial maneuverability, and verify the feasibility and reliability of control software.展开更多
A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engine...A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R＆D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine＇s working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.展开更多
To provide a suitable model for AUV simulation and control purposes, a general nonlinear dynamic model including a novel thruster hydrodynamics model was derived. Based on the modeling method, the "AUV-XX" s...To provide a suitable model for AUV simulation and control purposes, a general nonlinear dynamic model including a novel thruster hydrodynamics model was derived. Based on the modeling method, the "AUV-XX" simulation platform was established to carry out fundamental tests on its motion characteristics, stability, and controllability. A motion control strategy consisting of both position and speed control in a horizontal plane was designed for different task assignments of underwater vehicles. Combined control of heave and pitch was adopted to compensate for the reduction of vertical tunnel thrusters when the vehicle is moving at a high speed. An improved S-surface controller based on the capacitor plate model was developed with flexible gain selections made possible by different forms of restricting the error and changing the rate of the error. Simulation results show that the derived general mathematical model together with simulation platform can provide a test bed for fundamental tests of motion control. Additionally, the capacitor plate model S-surface control shows a good performance in guiding the vehicle to achieve the desired position and speed with sufficient accuracy.展开更多
In this paper, we propose a new formula of the real-time minimum safety headway based on the relative velocity of consecutive trains and present a dynamic model of high-speed passenger train movements in the rail line...In this paper, we propose a new formula of the real-time minimum safety headway based on the relative velocity of consecutive trains and present a dynamic model of high-speed passenger train movements in the rail line based on the proposed formula of the minimum safety headway. Moreover, we provide the control strategies of the high-speed passenger train operations based on the proposed formula of the real-time minimum safety headway and the dynamic model of highspeed passenger train movements. The simulation results demonstrate that the proposed control strategies of the passenger train operations can greatly reduce the delay propagation in the high-speed rail line when a random delay occurs.展开更多
In recent years, modelling crowd and evacuation dynamics has become very important, with increasing huge numbers of people gathering around the world for many reasons and events. The fact that our global population gr...In recent years, modelling crowd and evacuation dynamics has become very important, with increasing huge numbers of people gathering around the world for many reasons and events. The fact that our global population grows dramatically every year and the current public transport systems are able to transport large amounts of people heightens the risk of crowd panic or crush. Pedestrian models are based on macroscopic or microscopic behaviour. In this paper, we are interested in developing models that can be used for evacuation control strategies. This model will be based on microscopic pedestrian simulation models, and its evolution and design requires a lot of information and data. The people stream will be simulated, based on mathematical models derived from empirical data about pedestrian flows. This model is developed from image data bases, so called empirical data, taken from a video camera or data obtained using human detectors. We consider the individuals as autonomous particles interacting through social and physical forces, which is an approach that has been used to simulate crowd behaviour. The target of this work is to describe a comprehensive approach to model a huge number of pedestrians and to simulate high density crowd behaviour in overcrowding places, e.g. sport, concert and pilgrimage places, and to assist engineering in the resolution of complicated problems through integrating a number of models from different research domains.展开更多
The paper introduced a special approach for diesel’s all-speed-governor modeling, which, in some cases, could solve the knotty problem frequently met in computer simulation of diesel propulsion system or diesel gener...The paper introduced a special approach for diesel’s all-speed-governor modeling, which, in some cases, could solve the knotty problem frequently met in computer simulation of diesel propulsion system or diesel generating set. Suppose that it is hard to get a control-oriented governor mathematical model when the general approaches, the analytical approach or the experimental approach, are applied, and that an open-loop step response of the diesel engine and its system is available by means of computer simulation, the critical three parameters of a governor mathematical model, the proportional gain K_p, integral time constant K_i, and derivative time constant K_d, can be determined by use of PID tuning method which are widely applied in industrial process control. This paper discussed the train of thought of the approach, precondition, procedure, several modifications of the classical PID model, and some points for attention. A couple of case studies were given to demonstrate the effectiveness of this approach.展开更多
Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based ...Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based on the system dynamics methodology.The introduction of Wolbachia-carrying mosquitoes aims to reduce dengue transmission by interfering with the reproductive capacity of mosquitoes,thus limiting the spread of the virus.Objective:the objective of this study is to analyze how this intervention affects not only the incidence of dengue but also the health care system,evaluating changes in the demand for medical services and the costs associated with treatment in health care institutions.Specifically,it looks at the cost per visit to an Epidemiologist,a Family Doctor,diagnostic tests,and hospitalization.Methods:the study uses simulation scenarios to model the potential impact of the Wolbachia-based intervention in reducing dengue cases and its associated health and economic burden.The scenarios also assess the optimization of resources and improvements in the health system’s response to epidemic outbreaks.The simulation model utilizes real data from the Americas region to enhance the accuracy and relevance of the results.Conclusion:The results the potential of the release of Wolbachia-carrying mosquitoes to significantly mitigate the health and economic burden of dengue,with a maximum saving of 60.15%in the best simulation scenario.The approach not only highlights scientific innovation but also demonstrates its potential influence on public policy design.The findings support the implementation of sustainable strategies to maximize the benefits of this intervention and ensure its effective integration into public health programs,contributing to better long-term dengue management.展开更多
The resumption of production after the“suspension”caused by the COVID-19 has emerged as an urgent problem for many enterprises and the government.The resumption of production is actually a dynamic evolution problem ...The resumption of production after the“suspension”caused by the COVID-19 has emerged as an urgent problem for many enterprises and the government.The resumption of production is actually a dynamic evolution problem from 0 to 1(100%).This paper constructs a general game model and a dynamic replication system for the resumption of production and government support,and gives theorems for the construction of the model.It analyzes the evolution mechanism and scenario conditions for the convergence of enterprise strategies to the“resumption of production”strategy,takes the resumption of production of hog farmers as an example to carry out a study on the regulation of countermeasures to resume hog production,and explores systemic countermeasures and suggestions for the rapid convergence of farmers’strategies to the“resumption of work and production”strategy.The study found that the production resuming behavior system dynamics evolution game regulation model provides a systematic model and method for the study of resumption countermeasures,a general regulation model for the resumption ratio from 0 to 1(100%),and a systematic idea,method and model for exploring the“precise strategy”system to promote the rapid resumption of production.展开更多
The coexistence of pollution from coal-fired heating and inefficient utilization of renewable resources in northern China has raised great concern.Current studies on heat-power systems are primarily focused on traditi...The coexistence of pollution from coal-fired heating and inefficient utilization of renewable resources in northern China has raised great concern.Current studies on heat-power systems are primarily focused on traditional combined heat and power(CHP)systems and are limited to static energy flow analysis or the dynamic characteristics of a single system component.Hence,it is difficult to make full use of the complementary potential of electrical energy and heat energy.This paper proposes a heat-power station(HPS)system based on renewable energy for the purpose of utilizing the surplus renewable energy to generate heat and meet heating demands.The overall architecture of the HPS system is established and its operational principle and dynamic characteristics of both the electrical and heating components in the system are analyzed and dynamic mathematical models are also presented.In addition,a coordinated electro-thermal control method based on system characteristics is designed to ensure the normal operation of a HPS.Simulation results verify the effectiveness of the model and control in the case of renewables fuctuation and heat load variations.展开更多
Advanced driver assistance systems(ADAS) seek to provide drivers and passengers of automotive vehicles increased safety and comfort. Original equipment manufacturers are integrating and developing systems for distance...Advanced driver assistance systems(ADAS) seek to provide drivers and passengers of automotive vehicles increased safety and comfort. Original equipment manufacturers are integrating and developing systems for distance keeping, lane keeping and changing and other functionalities. The modern automobile is a complex system of systems. How the functionalities of advanced driver assistance are implemented and coordinated across the systems of the vehicle is generally not made available to the wider research community by the developers and manufactures. This paper seeks to begin filling this gap by assembling open source physics models of the vehicle dynamics and ADAS command models. Additionally, in order to facilitate ADAS development and testing without having access to the details of ADAS, a coordinated control architecture for motion management is also proposed for distributing ADAS motion control commands over vehicle systems. The architecture is demonstrated in a case study where motion is coordinated between the steering and the braking systems, which are typically used only for a single functionality. The integrated vehicle and system dynamics using the coordinated control architecture are simulated for various driving tasks. It is seen that improved trajectory following can be achieved by the proposed coordinated control architecture. The models, simulations and control architecture are made available for open access.展开更多
Recently many new types of small vehicles for future urban societies have been proposed and developed.Such small vehicles tends to have reduced stability and handling ability than conventional vehicles because of thei...Recently many new types of small vehicles for future urban societies have been proposed and developed.Such small vehicles tends to have reduced stability and handling ability than conventional vehicles because of their lighter weight and reduced tire performance.To cope with this problem by active collaboration of Japanese academia and industries,a benchmark problem of designing vehicle control logic for an articulated In-Wheel-Motor vehicle was settled by Japanese society of automotive industries and academia.For this purpose,simulation models of the new vehicle using multi-physics acausal modeling language Modelica were provided from the industry side.Challengers were requested to design controllers of tire steering angle,tire camber angle and tire driving force to satisfy requested vehicle dynamic characteristics.There also were some restrictions about the range of actuators.Four test scenarios were given to evaluate the control performance.Many challengers from Japanese Universities have tackled with this benchmark problem.Some results of their researches are also introduced in this paper.展开更多
With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant （WWTP） was produced and has been widely used. The dynamic change of the quality and ...With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant （WWTP） was produced and has been widely used. The dynamic change of the quality and flow of influent are major factors causing the unstable operation of wastewater treatment process. As a basic model, ASMI model was used for the simulation of activated sludge process, and double exponential model was selected for the simulation of secondary sedimentation tank. The influences of influent change to the aeration tank and secondary sedimentation tank were investigated, and the relationship among influent change, the quality of effluent and the level of sludge blanket in secondary sedimentation tank was established. On the basis of the simulation results, the operation of the WWTP could be adjusted under the dynamic change of the influent. Furthermore, the controlling strategy combined the feed-forward on the influent flow and the feedback on the level of sludge blanket in the secondary sedimentation tank was studied.展开更多
In this paper,we present a general formulation for a fractional optimal control problem (FOCP),in which the state and co-state equations are given in terms of the left fractional derivatives.We develop the forward-bac...In this paper,we present a general formulation for a fractional optimal control problem (FOCP),in which the state and co-state equations are given in terms of the left fractional derivatives.We develop the forward-backward sweep method (FBSM)using the Adamstype predictor-corrector method to solve the FOCP.We present a fractional model for transmission dynamics of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS)with treatment and incorporate three control efforts (effective use of condoms,ART treatment and behavioral change control)into the model aimed at controlling the spread of HIV/AIDS epidemic.The necessary conditions for fractional optimal control of the disease are derived and analyzed.The numerical results show that implementing all the control efforts increases the life time and the quality of life those living with HIV and decreases significantly the number of HIV-infected and AIDS people.Also,the maximum levels of the controls and the value of objective functional decrease when the derivative order a limits to 1(0.7≤a <1).In addition,the effect of the fractional derivative order a (0.7≤a <1)on the spread of HIV/AIDS epidemic and the treatment of HIV-infected population is investigated.The results show that the derivative order a can play the role of using ART treatment in the model.展开更多
As industrialization and informatization becomemore deeply intertwined,industrial control networks have entered an era of intelligence.The connection between industrial control networks and the external internet is be...As industrialization and informatization becomemore deeply intertwined,industrial control networks have entered an era of intelligence.The connection between industrial control networks and the external internet is becoming increasingly close,which leads to frequent security accidents.This paper proposes a model for the industrial control network.It includes a malware containment strategy that integrates intrusion detection,quarantine,and monitoring.Basedonthismodel,the role of keynodes in the spreadofmalware is studied,a comparisonexperiment is conducted to validate the impact of the containment strategy.In addition,the dynamic behavior of the model is analyzed,the basic reproduction number is computed,and the disease-free and endemic equilibrium of the model is also obtained by the basic reproduction number.Moreover,through simulation experiments,the effectiveness of the containment strategy is validated,the influence of the relevant parameters is analyzed,and the containment strategy is optimized.In otherwords,selective immunity to key nodes can effectively suppress the spread ofmalware andmaintain the stability of industrial control systems.The earlier the immunization of key nodes,the better.Once the time exceeds the threshold,immunizing key nodes is almost ineffective.The analysis provides a better way to contain the malware in the industrial control network.展开更多
Owing to the dynamics coupling between a free-floating base and a manipulator, the non-stationary base of a space robot will face the issue of base disturbance due to a manipulator＇s motion. The reaction torque acted...Owing to the dynamics coupling between a free-floating base and a manipulator, the non-stationary base of a space robot will face the issue of base disturbance due to a manipulator＇s motion. The reaction torque acted on the satellite base＇s centroid is an important index to measure the satellite base＇s disturbance. In this paper, a comprehensive analysis of the reaction torque is made, and a novel way to derive the analytical form of the reaction torque is proposed. In addition,the reaction torque null-space is derived, in which the manipulator＇s joint motion is dynamically decoupled from the motion of the satellite base, and its novel expression demonstrates the equivalence between the reaction torque null-space and the reaction null-space. Furthermore, the reaction torque acted as an optimization index can be utilized to achieve satellite base disturbance minimization in the generalized Jacobian-based end-effector Cartesian path tracking task. Besides, supposing that the redundant degrees of freedom are abundant to achieve reaction torque-based active control, the reaction torque can be used to realize satellite base attitude control, that is, base attitude adjustment or maintenance. Moreover, because reaction torque-based control is a second-order control scheme, joint torque minimization can be regarded as the optimization task in reaction torque-based active or in-active control. A real-time simulation system of a 7-DOF space robot under Linux/RTAI is developed to verify and test the feasibility and reliability of the proposed ideas. Our extensive empirical results demonstrate that the corresponding analysis about the reaction torque is correct and the proposed methods are feasible.展开更多
In this work we introduce the“Extensible Fish-tank Volume Model”that can reduce the complexity in the design and control of the Recirculating Aquaculture Systems.In the developed model we adjust the volume of a sing...In this work we introduce the“Extensible Fish-tank Volume Model”that can reduce the complexity in the design and control of the Recirculating Aquaculture Systems.In the developed model we adjust the volume of a single fish-tank to the prescribed values of stocking density,by controlling the necessary volume in each time step.Having developed an advantageous feeding,water exchange and oxygen supply strategy,as well as considering a compromise scheduling for the fingerling input and product fish output,we divide the volume vs.time function into equidistant parts and calculate the average volumes for these parts.Comparing these average values with the volumes of available tanks,we can plan the appropriate grades.The elaborated method is a good example for a case,where computational modeling is used to simulate a‘‘fictitious process model”that cannot be feasibly realized in the practice,but can simplify and accelerate the design and planning of real world processes by reducing the complexity.展开更多
基金Weapons Preliminary Research Key Foundation of China (9140A01010106HK0307)
文摘This article investigates the dynamic characteristics of deflectable nose missiles with rotary single-channel control. After introduction of effective attack and sideslip angles as well as quasi-body coordinates based on the spin characteristics of the missile＇s body, an integrated rigid kinetic model of missile with deflectable nose control is set up in the quasi-body coordinates considering the interaction between the missile＇s nose and body by using rootless multi-rigid-body system dynamics and is linearized. Then an analysis with simulation is conducted to investigate the coupling characteristics between the channels, the influences of nose deflection on the body and the dynamic characteristics of missile＇s body. The results indicate that various channels of missiles with deflectable nose control are coupled cross-linked; the nose deflection tends to make the body move in the opposite direction and, finally, evidences the correctness and reasonability of the kinetic model proposed by this article.
基金Sponsored by the National Natural Science Foundation of China (501222155)
文摘A 7 degree-of-freedom （DOF） 4 wheels vehicle dynamics model based on Matlab-Simulink is established,and 7 DOF vehicle dynamics equations in the form of nonlinear state-space standards are given.The characters of the electronic throttle and the active braking system have been analyzed.And the electronic throttle model and the active braking system model are built according to the test results respectively.Off-line simulation results indicate that the model is suitable for the vehicle adaptive cruise control system,and both of the electronic throttle and the active braking system work in a reasonable way.An adaptive cruise control （ACC） example illustrates that the model has a good performance in cruise and distance keeping.
文摘A first principles-based dynamic model for a continuous catalyst regeneration (CCR) platforming process, the UOP commercial naphtha catalytic reforming process, is developed in this paper. The lumping details of the naphtha feed and reaction scheme of the reaction model are given. The process model is composed of the reforming reaction model with catalyst deactivation, the furnace model and the separator model, which is capable of capturing the major dynamics that occurs in this process system. Dynamic simulations are performed based on Gear numerical algorithm and method of lines (MOL), a numerical technique dealing with partial differential equations (PDEs). The results of simulation are also presented. Dynamic responses caused by disturbances in the process system can be correctly predicted through simulations.
基金Supported by National Natural Science Foundation under Grant No.50879014
文摘Accurate modeling and simulation of autonomous underwater vehicle （AUV） is essential for autonomous control and maneuverability research. In this paper, a mini AUV- ＂MAUV-Ⅱ＂ was researched and the nonlinear mathematic model of the AUV in spatial motion was derived based on momentum theorem. The forces acting on AUV were resolved to several modules which were expressed in matrix form. Based on the motion model and combined with virtual reality technology, a motion simulation system was constructed. Considering the characteristic of ＂MAUV-Ⅱ ＂, the heading control and depth control were simulated by adopting S-surface control method. A long distance traveling simulation experiment based on target planning was also done. The simulation results show that the ＂MAUV-Ⅱ＂ has good spatial maneuverability, and verify the feasibility and reliability of control software.
基金Sponsored by the Ministerial Level Advanced Research(10660060220)
文摘A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R＆D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine＇s working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.
基金the National Science Foundation under Grant No.50879014,No.50909025
文摘To provide a suitable model for AUV simulation and control purposes, a general nonlinear dynamic model including a novel thruster hydrodynamics model was derived. Based on the modeling method, the "AUV-XX" simulation platform was established to carry out fundamental tests on its motion characteristics, stability, and controllability. A motion control strategy consisting of both position and speed control in a horizontal plane was designed for different task assignments of underwater vehicles. Combined control of heave and pitch was adopted to compensate for the reduction of vertical tunnel thrusters when the vehicle is moving at a high speed. An improved S-surface controller based on the capacitor plate model was developed with flexible gain selections made possible by different forms of restricting the error and changing the rate of the error. Simulation results show that the derived general mathematical model together with simulation platform can provide a test bed for fundamental tests of motion control. Additionally, the capacitor plate model S-surface control shows a good performance in guiding the vehicle to achieve the desired position and speed with sufficient accuracy.
基金supported by the National Basic Research Program of China (Grant No. 2012CB725400)the National Natural Science Foundation of China (Grant No. 71131001-1)the Research Foundation of State Key Laboratory of Rail Traffic Control and Safety,Beijing Jiaotong University,China (Grant Nos. RCS2012ZZ001 and RCS2012ZT001)
文摘In this paper, we propose a new formula of the real-time minimum safety headway based on the relative velocity of consecutive trains and present a dynamic model of high-speed passenger train movements in the rail line based on the proposed formula of the minimum safety headway. Moreover, we provide the control strategies of the high-speed passenger train operations based on the proposed formula of the real-time minimum safety headway and the dynamic model of highspeed passenger train movements. The simulation results demonstrate that the proposed control strategies of the passenger train operations can greatly reduce the delay propagation in the high-speed rail line when a random delay occurs.
文摘In recent years, modelling crowd and evacuation dynamics has become very important, with increasing huge numbers of people gathering around the world for many reasons and events. The fact that our global population grows dramatically every year and the current public transport systems are able to transport large amounts of people heightens the risk of crowd panic or crush. Pedestrian models are based on macroscopic or microscopic behaviour. In this paper, we are interested in developing models that can be used for evacuation control strategies. This model will be based on microscopic pedestrian simulation models, and its evolution and design requires a lot of information and data. The people stream will be simulated, based on mathematical models derived from empirical data about pedestrian flows. This model is developed from image data bases, so called empirical data, taken from a video camera or data obtained using human detectors. We consider the individuals as autonomous particles interacting through social and physical forces, which is an approach that has been used to simulate crowd behaviour. The target of this work is to describe a comprehensive approach to model a huge number of pedestrians and to simulate high density crowd behaviour in overcrowding places, e.g. sport, concert and pilgrimage places, and to assist engineering in the resolution of complicated problems through integrating a number of models from different research domains.
文摘The paper introduced a special approach for diesel’s all-speed-governor modeling, which, in some cases, could solve the knotty problem frequently met in computer simulation of diesel propulsion system or diesel generating set. Suppose that it is hard to get a control-oriented governor mathematical model when the general approaches, the analytical approach or the experimental approach, are applied, and that an open-loop step response of the diesel engine and its system is available by means of computer simulation, the critical three parameters of a governor mathematical model, the proportional gain K_p, integral time constant K_i, and derivative time constant K_d, can be determined by use of PID tuning method which are widely applied in industrial process control. This paper discussed the train of thought of the approach, precondition, procedure, several modifications of the classical PID model, and some points for attention. A couple of case studies were given to demonstrate the effectiveness of this approach.
文摘Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based on the system dynamics methodology.The introduction of Wolbachia-carrying mosquitoes aims to reduce dengue transmission by interfering with the reproductive capacity of mosquitoes,thus limiting the spread of the virus.Objective:the objective of this study is to analyze how this intervention affects not only the incidence of dengue but also the health care system,evaluating changes in the demand for medical services and the costs associated with treatment in health care institutions.Specifically,it looks at the cost per visit to an Epidemiologist,a Family Doctor,diagnostic tests,and hospitalization.Methods:the study uses simulation scenarios to model the potential impact of the Wolbachia-based intervention in reducing dengue cases and its associated health and economic burden.The scenarios also assess the optimization of resources and improvements in the health system’s response to epidemic outbreaks.The simulation model utilizes real data from the Americas region to enhance the accuracy and relevance of the results.Conclusion:The results the potential of the release of Wolbachia-carrying mosquitoes to significantly mitigate the health and economic burden of dengue,with a maximum saving of 60.15%in the best simulation scenario.The approach not only highlights scientific innovation but also demonstrates its potential influence on public policy design.The findings support the implementation of sustainable strategies to maximize the benefits of this intervention and ensure its effective integration into public health programs,contributing to better long-term dengue management.
文摘The resumption of production after the“suspension”caused by the COVID-19 has emerged as an urgent problem for many enterprises and the government.The resumption of production is actually a dynamic evolution problem from 0 to 1(100%).This paper constructs a general game model and a dynamic replication system for the resumption of production and government support,and gives theorems for the construction of the model.It analyzes the evolution mechanism and scenario conditions for the convergence of enterprise strategies to the“resumption of production”strategy,takes the resumption of production of hog farmers as an example to carry out a study on the regulation of countermeasures to resume hog production,and explores systemic countermeasures and suggestions for the rapid convergence of farmers’strategies to the“resumption of work and production”strategy.The study found that the production resuming behavior system dynamics evolution game regulation model provides a systematic model and method for the study of resumption countermeasures,a general regulation model for the resumption ratio from 0 to 1(100%),and a systematic idea,method and model for exploring the“precise strategy”system to promote the rapid resumption of production.
基金supported by the State Grid Corporation of China under Grant 521500190017.
文摘The coexistence of pollution from coal-fired heating and inefficient utilization of renewable resources in northern China has raised great concern.Current studies on heat-power systems are primarily focused on traditional combined heat and power(CHP)systems and are limited to static energy flow analysis or the dynamic characteristics of a single system component.Hence,it is difficult to make full use of the complementary potential of electrical energy and heat energy.This paper proposes a heat-power station(HPS)system based on renewable energy for the purpose of utilizing the surplus renewable energy to generate heat and meet heating demands.The overall architecture of the HPS system is established and its operational principle and dynamic characteristics of both the electrical and heating components in the system are analyzed and dynamic mathematical models are also presented.In addition,a coordinated electro-thermal control method based on system characteristics is designed to ensure the normal operation of a HPS.Simulation results verify the effectiveness of the model and control in the case of renewables fuctuation and heat load variations.
基金supported by the Programme for Simulation Innovation(PSI)
文摘Advanced driver assistance systems(ADAS) seek to provide drivers and passengers of automotive vehicles increased safety and comfort. Original equipment manufacturers are integrating and developing systems for distance keeping, lane keeping and changing and other functionalities. The modern automobile is a complex system of systems. How the functionalities of advanced driver assistance are implemented and coordinated across the systems of the vehicle is generally not made available to the wider research community by the developers and manufactures. This paper seeks to begin filling this gap by assembling open source physics models of the vehicle dynamics and ADAS command models. Additionally, in order to facilitate ADAS development and testing without having access to the details of ADAS, a coordinated control architecture for motion management is also proposed for distributing ADAS motion control commands over vehicle systems. The architecture is demonstrated in a case study where motion is coordinated between the steering and the braking systems, which are typically used only for a single functionality. The integrated vehicle and system dynamics using the coordinated control architecture are simulated for various driving tasks. It is seen that improved trajectory following can be achieved by the proposed coordinated control architecture. The models, simulations and control architecture are made available for open access.
文摘Recently many new types of small vehicles for future urban societies have been proposed and developed.Such small vehicles tends to have reduced stability and handling ability than conventional vehicles because of their lighter weight and reduced tire performance.To cope with this problem by active collaboration of Japanese academia and industries,a benchmark problem of designing vehicle control logic for an articulated In-Wheel-Motor vehicle was settled by Japanese society of automotive industries and academia.For this purpose,simulation models of the new vehicle using multi-physics acausal modeling language Modelica were provided from the industry side.Challengers were requested to design controllers of tire steering angle,tire camber angle and tire driving force to satisfy requested vehicle dynamic characteristics.There also were some restrictions about the range of actuators.Four test scenarios were given to evaluate the control performance.Many challengers from Japanese Universities have tackled with this benchmark problem.Some results of their researches are also introduced in this paper.
文摘With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant （WWTP） was produced and has been widely used. The dynamic change of the quality and flow of influent are major factors causing the unstable operation of wastewater treatment process. As a basic model, ASMI model was used for the simulation of activated sludge process, and double exponential model was selected for the simulation of secondary sedimentation tank. The influences of influent change to the aeration tank and secondary sedimentation tank were investigated, and the relationship among influent change, the quality of effluent and the level of sludge blanket in secondary sedimentation tank was established. On the basis of the simulation results, the operation of the WWTP could be adjusted under the dynamic change of the influent. Furthermore, the controlling strategy combined the feed-forward on the influent flow and the feedback on the level of sludge blanket in the secondary sedimentation tank was studied.
文摘In this paper,we present a general formulation for a fractional optimal control problem (FOCP),in which the state and co-state equations are given in terms of the left fractional derivatives.We develop the forward-backward sweep method (FBSM)using the Adamstype predictor-corrector method to solve the FOCP.We present a fractional model for transmission dynamics of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS)with treatment and incorporate three control efforts (effective use of condoms,ART treatment and behavioral change control)into the model aimed at controlling the spread of HIV/AIDS epidemic.The necessary conditions for fractional optimal control of the disease are derived and analyzed.The numerical results show that implementing all the control efforts increases the life time and the quality of life those living with HIV and decreases significantly the number of HIV-infected and AIDS people.Also,the maximum levels of the controls and the value of objective functional decrease when the derivative order a limits to 1(0.7≤a <1).In addition,the effect of the fractional derivative order a (0.7≤a <1)on the spread of HIV/AIDS epidemic and the treatment of HIV-infected population is investigated.The results show that the derivative order a can play the role of using ART treatment in the model.
基金Scientific Research Project of Liaoning Province Education Department,Code:LJKQZ20222457&LJKMZ20220781Liaoning Province Nature Fund Project,Code:No.2022-MS-291.
文摘As industrialization and informatization becomemore deeply intertwined,industrial control networks have entered an era of intelligence.The connection between industrial control networks and the external internet is becoming increasingly close,which leads to frequent security accidents.This paper proposes a model for the industrial control network.It includes a malware containment strategy that integrates intrusion detection,quarantine,and monitoring.Basedonthismodel,the role of keynodes in the spreadofmalware is studied,a comparisonexperiment is conducted to validate the impact of the containment strategy.In addition,the dynamic behavior of the model is analyzed,the basic reproduction number is computed,and the disease-free and endemic equilibrium of the model is also obtained by the basic reproduction number.Moreover,through simulation experiments,the effectiveness of the containment strategy is validated,the influence of the relevant parameters is analyzed,and the containment strategy is optimized.In otherwords,selective immunity to key nodes can effectively suppress the spread ofmalware andmaintain the stability of industrial control systems.The earlier the immunization of key nodes,the better.Once the time exceeds the threshold,immunizing key nodes is almost ineffective.The analysis provides a better way to contain the malware in the industrial control network.
基金supported in part by the National Program on Key Basic Research Project 973 Program under Grant 2013CB733103the Program for New Century Excellent Talents in University under Grand NCET-10-0058
文摘Owing to the dynamics coupling between a free-floating base and a manipulator, the non-stationary base of a space robot will face the issue of base disturbance due to a manipulator＇s motion. The reaction torque acted on the satellite base＇s centroid is an important index to measure the satellite base＇s disturbance. In this paper, a comprehensive analysis of the reaction torque is made, and a novel way to derive the analytical form of the reaction torque is proposed. In addition,the reaction torque null-space is derived, in which the manipulator＇s joint motion is dynamically decoupled from the motion of the satellite base, and its novel expression demonstrates the equivalence between the reaction torque null-space and the reaction null-space. Furthermore, the reaction torque acted as an optimization index can be utilized to achieve satellite base disturbance minimization in the generalized Jacobian-based end-effector Cartesian path tracking task. Besides, supposing that the redundant degrees of freedom are abundant to achieve reaction torque-based active control, the reaction torque can be used to realize satellite base attitude control, that is, base attitude adjustment or maintenance. Moreover, because reaction torque-based control is a second-order control scheme, joint torque minimization can be regarded as the optimization task in reaction torque-based active or in-active control. A real-time simulation system of a 7-DOF space robot under Linux/RTAI is developed to verify and test the feasibility and reliability of the proposed ideas. Our extensive empirical results demonstrate that the corresponding analysis about the reaction torque is correct and the proposed methods are feasible.
基金The research is supported by the Bilateral Chinese-Hungarian project in the frame of TE´T_12_CN-1-2012-0041 project.
文摘In this work we introduce the“Extensible Fish-tank Volume Model”that can reduce the complexity in the design and control of the Recirculating Aquaculture Systems.In the developed model we adjust the volume of a single fish-tank to the prescribed values of stocking density,by controlling the necessary volume in each time step.Having developed an advantageous feeding,water exchange and oxygen supply strategy,as well as considering a compromise scheduling for the fingerling input and product fish output,we divide the volume vs.time function into equidistant parts and calculate the average volumes for these parts.Comparing these average values with the volumes of available tanks,we can plan the appropriate grades.The elaborated method is a good example for a case,where computational modeling is used to simulate a‘‘fictitious process model”that cannot be feasibly realized in the practice,but can simplify and accelerate the design and planning of real world processes by reducing the complexity.
