The simulation techniques of hardware-in-loop simulation(HLS) of homing antitank missile based on the personal computer (PC) are discussed. The PC and MCS-96 chip controller employ A/D and D/A boards (with photoelectr...The simulation techniques of hardware-in-loop simulation(HLS) of homing antitank missile based on the personal computer (PC) are discussed. The PC and MCS-96 chip controller employ A/D and D/A boards (with photoelectricity isolation) to transfer measur ment and control information about homing head, gyro and rudder and utilize the digital hand shaking board to build correct communication communication protocol. In order to satisfy the real-time requirement of HLS, this paper first simplifies the aerodynamic data file reasonably, then builds a PC software with C language. The program of the controller part is made with PL/M language. The simulation of HLS based on PC is done with the same sampling period of 10ms as that of YH-F1 and the experiment results are identical to those of digital simulation of the homing anti-tank guided missile.展开更多
A controllable hydrostatic thrust bearing was presented to improve rigidity. The bearing worktable poses were controlled by coupling oilfilm thickness of four controllable chambers. The chamber flow can be regulated b...A controllable hydrostatic thrust bearing was presented to improve rigidity. The bearing worktable poses were controlled by coupling oilfilm thickness of four controllable chambers. The chamber flow can be regulated by electro hydraulic servo valve-control variable pump according to the surface roughness, load, cutting force, and thermal effects of worktable. The mathematical models of the controllable chamber flow, servo variable mechanism and controller were built. The pose control model was established, which contained the kinematics positive and negative solution and control strategy of feedforward and hydraulic cylinder position feedback. Hardware-in-loop simulation experiment was carried out on the electro hydraulic servo test bench by means of the non-linear relation of film thickness and hydraulic cylinder displacement. Hardware-in-loop simulation experiment results show that the controllable bearings exhibit high oilfilm rigidity, the rising time is 0.24 s and the maximum overshoot is 2.23%, and can be applied in high precision heavy machine tool.展开更多
This paper described an effective method to implement human & hardware in the loop simulation(HHILS), which is based on MATLAB system and can be used to study human driving actions in the abrupt situation and vehi...This paper described an effective method to implement human & hardware in the loop simulation(HHILS), which is based on MATLAB system and can be used to study human driving actions in the abrupt situation and vehicle stability control(VSC). A hybrid control algorithm, which makes full use of the advantages of robust control and fuzzy logic, was adopted in VSC system. The results of HHILS show that HHILS’ application on the vehicle handling and VSC resarch is feasible. These results also confirm that the handling performance of the vehicle with VSC is improved obviously compared to the vehicle without VSC.展开更多
In order to facilitate the teaching of industrial processes and experiments on the twin-screw extruder control debugging,and be closer to the actual testing,to reduce the debugging costs and the risk of debugging proc...In order to facilitate the teaching of industrial processes and experiments on the twin-screw extruder control debugging,and be closer to the actual testing,to reduce the debugging costs and the risk of debugging process,the paper designs a hardware-in-loop simulation of twin-screw extruder experiment system which is closer to scene,low cost and high safety.The system through the establishment of twin-screw extruder’s mathematical model on computer to simulate the realistic system and there is hardware practicality in the computer simulation loop.The hardware based on C8051F020 can operate in the simulation loop in real time.In computer software design, we desigh man-machine interface that is intuitive and easy to operate,can reflect twin-screw extruder main operation information vividly.Finally,twin-screw extruder’s 3 heater temperature mathematical model and PID incremental control algorithm are presented.展开更多
FSC （Fractionated Spacecraft Cluster） is a kind of loosely distributed space system which is comprised of multiple physically independent spacecrafts orbiting closely and interactively communicating via wireless net...FSC （Fractionated Spacecraft Cluster） is a kind of loosely distributed space system which is comprised of multiple physically independent spacecrafts orbiting closely and interactively communicating via wireless network. Spaceborne ad-hoc network, as the physical infrastructure for information exchanging, is one of the enabling technologies of FSC. The demonstration of FSC flying supported by ad-hoc network is worth for the sake of proving the rationality of FSC and seeking technological improvements. Considering this, a NNP （Network Node Prototype） for spaceborne ad-hoc network is developed in this paper, which transmits the information required by the FSC cooperation. Four NNPs are then built up and collaborated into a hardware-in-loop simulation system, in which a typical loose satellite cluster flying mission was performed. The simulation results showed that the NNPs can support the inter-satellite communication for satellite cluster flying.展开更多
The path-following control design for an autonomous underwater vehicle(AUV)requires prior full or partial knowledge about the mathematical model defined through Newton’s second law based on a geometrical investigatio...The path-following control design for an autonomous underwater vehicle(AUV)requires prior full or partial knowledge about the mathematical model defined through Newton’s second law based on a geometrical investigation.AUV dynamics are highly nonlinear and time-varying,facing unpredictable disturbances due to AUVs operating in deep,hazardous oceanic environments.Consequently,navigation guidance and control systems for AUVs must learn and adapt to the time-varying dynamics of the nonlinear fully coupled vehicle model in the presence of highly unstructured underwater operating conditions.Many control engineers focus on the application of robust model-free adaptive control techniques in AUV maneuvers.Hence,the main goal is to design a novel salp swarm optimization of super twisting algorithm-based secondorder sliding mode controller for the planar path-following control of an AUV through regulation of the heading angle parameter.The finite time for tracking error convergence in the horizontal plane is provided through the control structure architecture,particularly for lateral deviations from the desired path.The proposed control law is designed such that it steers a robotic vehicle to track a predefined planar path at a constant speed determined by an end-user,without any temporal specification.Finally,the efficacy and tracking accuracy are evaluated through comparative analysis based on simulation and experimental hardware-in-loop assessment without violating the input constraints.Moreover,the proposed control law can handle parametric uncertainties and unpredictable disturbances such as ocean currents,wind,and measurement noise.展开更多
The design of a turbofan rotor speed control system, using model reference adaptive control（MRAC） method with input and output measurements, is discussed for the purpose of practical application. The nonlinear compe...The design of a turbofan rotor speed control system, using model reference adaptive control（MRAC） method with input and output measurements, is discussed for the purpose of practical application. The nonlinear compensator based on functional link neural network is used to deal with the engine nonlinearity and the hardware-in-loop simulation is also developed. The results show that the nonlinear MRAC controller has the adequate performance of compensating and adapting nonlinearity arising from the change of engine state or working environment. Such feature demonstrates potential practical applications of MRAC for aeroengine control system.展开更多
Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness t...Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness testing for embedded software systems. It is a system-level black-box testing approach in which the fault behaviors of embedded software is triggered with the aid of modelbased fault injection by the support of an executable model-driven hardware-in-loop （HIL） testing environment. The prototype implementation of the robustness testing environment based on the proposed approach is experimentally discussed and illustrated by industrial case studies based on several avionics-embedded software systems. The results show that our proposed and implemented robustness testing method and environment are effective to find more bugs, and reduce burdens of testing engineers to enhance efficiency of testing tasks, especially for testing complex embedded systems.展开更多
Flywheel Energy Storage System (FESS) is used as an energy regeneration system to help with reducing peak power requirements on RTG cranes that are used to load or unload container ships. Nevertheless, with the use of...Flywheel Energy Storage System (FESS) is used as an energy regeneration system to help with reducing peak power requirements on RTG cranes that are used to load or unload container ships. Nevertheless, with the use of FESS, Port Operator can deploy undersized generator for new RTG as this will further reduce fuel consumption. This paper presents the investigation of the amount of energy and fuel consumption that can be reduced in Rubber Tyred Gantry (RTG) cranes in container terminals by the use of simulation. In addition, Variable Speed Generator is integrated to the simulation-hybridized RTG. Simulation results reveal that the total energy saving exceeded 30% relatively to conventional RTG. A hardware-in-loop system is introduced for the purpose of validating the simulation results. The hardware components procured include a FESS, a Variable Frequency Drive (VFD) and brake resistors.展开更多
Abstract Spreading of nanofluids on solid substrate was studied via molecular dynamics simulations. Simulation models for two immiscible fluids （oil and water based nanofiuids） confined in a slit between two planar ...Abstract Spreading of nanofluids on solid substrate was studied via molecular dynamics simulations. Simulation models for two immiscible fluids （oil and water based nanofiuids） confined in a slit between two planar solid walls were set up. The influence of the volume concentration of the nanoparticles on the three-phase contact line motion was investigated. We found that the larger volume concentration results in more visible nanoparticle adsorption on solid surface. This effect further induces an advancing displacement of the contact line compared with the meniscus profiles in low concentration case and that with the absence of nanoparticles. These findings are consistent with the previous experimental and theoretical results and provide the atomic-scale understanding on nanofluid spreading.展开更多
This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor ...This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor driver to rotate the motor.The torque distribution of motors is studied in this paper actually.Firstly,the model of the EMB system is established.Then the state observer is developed to estimate the vehicle states including the vehicle velocity and longitudinal force.Due to the fact that the EMB system is nonlinear and uncertain,a FSMC strategy based on wheel slip ratio is proposed,where both the normal and emergency braking conditions are taken into account.The equivalent control law of sliding mode controller is designed on the basis of the variation of the front axle and rear axle load during the brake process,while the switching control law is adjusted by the fuzzy corrector.The simulation results illustrate that the FSMC strategy has the superior performance,better adaptability to various types of roads,and shorter braking distance,as compared to PID control and traditional sliding mode control technologies.Finally,the hardware-in-loop(HIL)experimental results have exemplified the validation of the developed methodology.展开更多
According to Maxwell electromagnetic field theory and magnetic vector potential integral equation,a mathematical model of LMF(Level Magnetic Field)for EMBR(Electromagnetic brake)was proposed,and the reliable software ...According to Maxwell electromagnetic field theory and magnetic vector potential integral equation,a mathematical model of LMF(Level Magnetic Field)for EMBR(Electromagnetic brake)was proposed,and the reliable software for LMF calculation was developed.The distribution of magnetic flux density given by numerical simulation shows that the magnetic flux density is greater in the magnet and magnetic leakage is observed in the gap.The magnetic flux density is uniform in horizontal plane and a peak is observed in vertical plane.Furthermore,the effects of electromagnetic and structural parameters on magnetic flux density were discussed.The relationship between magnetic flux,electromagnetic parameters and structural parameters is obtained by dimensional analysis,simulation experiment and least square method.展开更多
We investigate the Eulerian bond-cubic model on the square lattice by means of Monte Carlo simulations, using an efficient cluster algorithm and a finite-size scaling analysis. The critical points and four critical ex...We investigate the Eulerian bond-cubic model on the square lattice by means of Monte Carlo simulations, using an efficient cluster algorithm and a finite-size scaling analysis. The critical points and four critical exponents of the model are determined for several values of n. Two of the exponents are fractal dimensions, which are obtained numerically for the first time. Our results are consistent with the Coulomb gas predictions for the critical O（n） branch for n 〈 2 and the results obtained by previous transfer matrix calculations. For n = 2, we find that the thermal exponent, the magnetic exponent and the fractal dimension of the largest critical Eulerian bond component are different from those of the critical 0（2） loop model. These results confirm that the cubic anisotropy is marginal at n = 2 but irrelevant for n〈2.展开更多
Auditorium buildings are special structures needing much attention for it to function properly. Generally, consideration should be given to seating, sightlines, and acoustic requirements. In addition, the design shoul...Auditorium buildings are special structures needing much attention for it to function properly. Generally, consideration should be given to seating, sightlines, and acoustic requirements. In addition, the design should ensure performer-audience intimacy as much as possible. The focus of the study is to review design strategies for auditoria on the Kwame Nkrumah University of Science and Technology, Kumasi campus towards compliance and to develop solutions for improvements that will enhance the performance of 4 selected auditorium facilities. Case study, observation and measurements were the main strategies used. The results revealed that the approaches involved in auditorium designs are shape, volume, surface boundary dimensions and materials, stage, seating, foyers and sightlines. These parameters are grouped under acoustical, functional and programmatic parameters. Reverberation time calculated was high which indicated speech intelligibility problems, hence, improvement efforts were made to change the floor materials from polished tiles to carpeted floors, and high absorption wall claddings. In the process, the reverberation time was reduced from 1.47 - 2.23 to 0.84 - 1.73 for the studied buildings. The study recommends strict adherence to standards and guidelines, and for designers to have a keen focus on designing these special buildings. A renovation effort when undertaken, will lead to improvements in the performance of the selected buildings.展开更多
The servo system actuated by oscillating pneumatic cylinder for X-Y plate is a multi-variable nonlinear control system. Its mathematical model is established, and nonlinear factors are analyzed. Due to the existence o...The servo system actuated by oscillating pneumatic cylinder for X-Y plate is a multi-variable nonlinear control system. Its mathematical model is established, and nonlinear factors are analyzed. Due to the existence of deadlock zone and the small damp of the pneumatic oscillating cylinder, it is likely to result in overshoot, and there is also certain steady-state error, so online modifying of proportion-integration-differentiation （PID） parameters is needed so as to achieve better control performance. Meanwhile considering the stability demand for long-term run, a fuzzy adaptive PID controller is designed. The result of hardware-inloop （HIL） test and real-time control experiment shows that the adaptive PID controller has desirable serfadaptability and robustness to external disturbance and to change of system parameters, and its control per- fonnance is better than that of traditional PID controllers.展开更多
The development of low-carbon energy systems and renewable energy sources(RESs)are critical to solving the energy crisis around the world.However,renewable energy gen eration control strategies lead to fault character...The development of low-carbon energy systems and renewable energy sources(RESs)are critical to solving the energy crisis around the world.However,renewable energy gen eration control strategies lead to fault characteristics such as fault current amplitude limitation and phase angle distortion.Focusing on large-scale renewable energy transmission lines,the sensitivity of traditional current differential protection and distance protection may be reduced,and there is even the risk of maloperation.Therefore,a suitable transmission line model is established,which considers the distributed capacitance.Af terward,a novel dynamic state estimation based protection(DSEBP)for large-scale renewable energy transmission lines is proposed.The proposed DSEBP adopts instantaneous measure ments and additional protection criteria to ensure the quick ac tion and reliability.Finally,faults are identified by checking the matching degree between the actual measurements and the es tablished transmission line model.The performance of the pro posed DSEBP is verified through PSCAD/EMTDC and realtime digital simulator(RTDS)hardware-in-loop tests.The re sults demonstrate that the proposed DSEBP can identify vari ous types of faults quickly and reliably.Meanwhile,the pro posed DSEBP has a better capability to withstand fault resis tance and disturbance.展开更多
The popularization of smartphones and the acceleration of their replacement lead to a surge in mobile phone disposal.How to recycle waste mobile phones efficiently becomes a major problem in today’s society.The“Inte...The popularization of smartphones and the acceleration of their replacement lead to a surge in mobile phone disposal.How to recycle waste mobile phones efficiently becomes a major problem in today’s society.The“Internet+”recycling mode is an effective way to solve this problem.The recycling process of waste mobile phones involves retailers,manufacturers,third parties and other recycling parts.Retailers have natural advantages compared with other parts because of their perfect sales network and logistics system.The system dynamics model for“Internet+”recycling of waste mobile phones dominated by retailers is constructed,and the Vensim software is used to simulate the influence of changes in two key factors in“Internet+”recycling environment:Annual operating cost of online platform and offline unit logistics cost on retailers’recycling volume and recycling profit.The results show that the investment of online platform operation cost is conducive to the increase of retailers’online waste mobile phone recycling volume and recycling profit,while the investment of offline logistics cost increases retailers’online waste mobile phone recycling volume,but reduces the recycling profit.展开更多
In the paper,a novel self-learning energy management strategy(EMS)is proposed for fuel cell hybrid electric vehicles(FCHEV)to achieve the hydrogen saving and maintain the battery operation.In the EMS,it is proposed to...In the paper,a novel self-learning energy management strategy(EMS)is proposed for fuel cell hybrid electric vehicles(FCHEV)to achieve the hydrogen saving and maintain the battery operation.In the EMS,it is proposed to approximate the EMS policy function with fuzzy inference system(FIS)and learn the policy parameters through policy gradient reinforcement learning(PGRL).Thus,a so-called Fuzzy REINFORCE algorithm is first proposed and studied for EMS problem in the paper.Fuzzy REINFORCE is a model-free method that the EMS agent can learn itself through interactions with environment,which makes it independent of model accuracy,prior knowledge,and expert experience.Meanwhile,to stabilize the training process,a fuzzy baseline function is adopted to approximate the value function based on FIS without affecting the policy gradient direction.More-over,the drawbacks of traditional reinforcement learning such as high computation burden,long convergence time,can also be overcome.The effectiveness of the proposed methods were verified by Hardware-in-Loop ex-periments.The adaptability of the proposed method to the changes of driving conditions and system states is also verified.展开更多
Performance and energy consumption of high performance computing （HPC） interconnection networks have a great significance in the whole supercomputer, and building up HPC interconnection network simulation plat- form...Performance and energy consumption of high performance computing （HPC） interconnection networks have a great significance in the whole supercomputer, and building up HPC interconnection network simulation plat- form is very important for the research on HPC software and hardware technologies. To effectively evaluate the per- formance and energy consumption of HPC interconnection networks, this article designs and implements a detailed and clock-driven HPC interconnection network simulation plat- form, called HPC-NetSim. HPC-NetSim uses application- driven workloads and inherits the characteristics of the de- tailed and flexible cycle-accurate network simulator. Besides, it offers a large set of configurable network parameters in terms of topology and routing, and supports router＇s on/off states. We compare the simulated execution time with the real execution time of Tianhe-2 subsystem and the mean error is only 2.7%. In addition, we simulate the network behaviors with different network structures and low-power modes. The results are also consistent with the theoretical analyses.展开更多
文摘The simulation techniques of hardware-in-loop simulation(HLS) of homing antitank missile based on the personal computer (PC) are discussed. The PC and MCS-96 chip controller employ A/D and D/A boards (with photoelectricity isolation) to transfer measur ment and control information about homing head, gyro and rudder and utilize the digital hand shaking board to build correct communication communication protocol. In order to satisfy the real-time requirement of HLS, this paper first simplifies the aerodynamic data file reasonably, then builds a PC software with C language. The program of the controller part is made with PL/M language. The simulation of HLS based on PC is done with the same sampling period of 10ms as that of YH-F1 and the experiment results are identical to those of digital simulation of the homing anti-tank guided missile.
基金Project(20050214001) supported by Doctor Foundation of Education Ministry of ChinaProject(GC05A512) and supported by the Program of Heilongjiang Province Science and Technology, ChinaProject(zjg0702-01) supported by the Natural Science Foundation of Heilongjiang Province, China
文摘A controllable hydrostatic thrust bearing was presented to improve rigidity. The bearing worktable poses were controlled by coupling oilfilm thickness of four controllable chambers. The chamber flow can be regulated by electro hydraulic servo valve-control variable pump according to the surface roughness, load, cutting force, and thermal effects of worktable. The mathematical models of the controllable chamber flow, servo variable mechanism and controller were built. The pose control model was established, which contained the kinematics positive and negative solution and control strategy of feedforward and hydraulic cylinder position feedback. Hardware-in-loop simulation experiment was carried out on the electro hydraulic servo test bench by means of the non-linear relation of film thickness and hydraulic cylinder displacement. Hardware-in-loop simulation experiment results show that the controllable bearings exhibit high oilfilm rigidity, the rising time is 0.24 s and the maximum overshoot is 2.23%, and can be applied in high precision heavy machine tool.
文摘This paper described an effective method to implement human & hardware in the loop simulation(HHILS), which is based on MATLAB system and can be used to study human driving actions in the abrupt situation and vehicle stability control(VSC). A hybrid control algorithm, which makes full use of the advantages of robust control and fuzzy logic, was adopted in VSC system. The results of HHILS show that HHILS’ application on the vehicle handling and VSC resarch is feasible. These results also confirm that the handling performance of the vehicle with VSC is improved obviously compared to the vehicle without VSC.
文摘In order to facilitate the teaching of industrial processes and experiments on the twin-screw extruder control debugging,and be closer to the actual testing,to reduce the debugging costs and the risk of debugging process,the paper designs a hardware-in-loop simulation of twin-screw extruder experiment system which is closer to scene,low cost and high safety.The system through the establishment of twin-screw extruder’s mathematical model on computer to simulate the realistic system and there is hardware practicality in the computer simulation loop.The hardware based on C8051F020 can operate in the simulation loop in real time.In computer software design, we desigh man-machine interface that is intuitive and easy to operate,can reflect twin-screw extruder main operation information vividly.Finally,twin-screw extruder’s 3 heater temperature mathematical model and PID incremental control algorithm are presented.
文摘FSC （Fractionated Spacecraft Cluster） is a kind of loosely distributed space system which is comprised of multiple physically independent spacecrafts orbiting closely and interactively communicating via wireless network. Spaceborne ad-hoc network, as the physical infrastructure for information exchanging, is one of the enabling technologies of FSC. The demonstration of FSC flying supported by ad-hoc network is worth for the sake of proving the rationality of FSC and seeking technological improvements. Considering this, a NNP （Network Node Prototype） for spaceborne ad-hoc network is developed in this paper, which transmits the information required by the FSC cooperation. Four NNPs are then built up and collaborated into a hardware-in-loop simulation system, in which a typical loose satellite cluster flying mission was performed. The simulation results showed that the NNPs can support the inter-satellite communication for satellite cluster flying.
文摘The path-following control design for an autonomous underwater vehicle(AUV)requires prior full or partial knowledge about the mathematical model defined through Newton’s second law based on a geometrical investigation.AUV dynamics are highly nonlinear and time-varying,facing unpredictable disturbances due to AUVs operating in deep,hazardous oceanic environments.Consequently,navigation guidance and control systems for AUVs must learn and adapt to the time-varying dynamics of the nonlinear fully coupled vehicle model in the presence of highly unstructured underwater operating conditions.Many control engineers focus on the application of robust model-free adaptive control techniques in AUV maneuvers.Hence,the main goal is to design a novel salp swarm optimization of super twisting algorithm-based secondorder sliding mode controller for the planar path-following control of an AUV through regulation of the heading angle parameter.The finite time for tracking error convergence in the horizontal plane is provided through the control structure architecture,particularly for lateral deviations from the desired path.The proposed control law is designed such that it steers a robotic vehicle to track a predefined planar path at a constant speed determined by an end-user,without any temporal specification.Finally,the efficacy and tracking accuracy are evaluated through comparative analysis based on simulation and experimental hardware-in-loop assessment without violating the input constraints.Moreover,the proposed control law can handle parametric uncertainties and unpredictable disturbances such as ocean currents,wind,and measurement noise.
文摘The design of a turbofan rotor speed control system, using model reference adaptive control（MRAC） method with input and output measurements, is discussed for the purpose of practical application. The nonlinear compensator based on functional link neural network is used to deal with the engine nonlinearity and the hardware-in-loop simulation is also developed. The results show that the nonlinear MRAC controller has the adequate performance of compensating and adapting nonlinearity arising from the change of engine state or working environment. Such feature demonstrates potential practical applications of MRAC for aeroengine control system.
基金the Aeronautics Science Foundation of China(No.2011ZD51055)Science and Technology on Reliability&Environmental Engineering Laboratory(No.302367)the National Pre-Research Foundation of China(No.51319080201)
文摘Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness testing for embedded software systems. It is a system-level black-box testing approach in which the fault behaviors of embedded software is triggered with the aid of modelbased fault injection by the support of an executable model-driven hardware-in-loop （HIL） testing environment. The prototype implementation of the robustness testing environment based on the proposed approach is experimentally discussed and illustrated by industrial case studies based on several avionics-embedded software systems. The results show that our proposed and implemented robustness testing method and environment are effective to find more bugs, and reduce burdens of testing engineers to enhance efficiency of testing tasks, especially for testing complex embedded systems.
文摘Flywheel Energy Storage System (FESS) is used as an energy regeneration system to help with reducing peak power requirements on RTG cranes that are used to load or unload container ships. Nevertheless, with the use of FESS, Port Operator can deploy undersized generator for new RTG as this will further reduce fuel consumption. This paper presents the investigation of the amount of energy and fuel consumption that can be reduced in Rubber Tyred Gantry (RTG) cranes in container terminals by the use of simulation. In addition, Variable Speed Generator is integrated to the simulation-hybridized RTG. Simulation results reveal that the total energy saving exceeded 30% relatively to conventional RTG. A hardware-in-loop system is introduced for the purpose of validating the simulation results. The hardware components procured include a FESS, a Variable Frequency Drive (VFD) and brake resistors.
基金supported by the National Natural Science Foundation of China(11172289,U1262103,and 11302218)Anhui Provincial Natural Science Foundation(1308085QA10)+1 种基金China Postdoctoral Science Foundation(2012M521243)the Fundamental Research Funds for the Central Universities of China(WK2090050022 and WK20900050027)
文摘Abstract Spreading of nanofluids on solid substrate was studied via molecular dynamics simulations. Simulation models for two immiscible fluids （oil and water based nanofiuids） confined in a slit between two planar solid walls were set up. The influence of the volume concentration of the nanoparticles on the three-phase contact line motion was investigated. We found that the larger volume concentration results in more visible nanoparticle adsorption on solid surface. This effect further induces an advancing displacement of the contact line compared with the meniscus profiles in low concentration case and that with the absence of nanoparticles. These findings are consistent with the previous experimental and theoretical results and provide the atomic-scale understanding on nanofluid spreading.
基金This work was supported by the National Natural Science Foundation of China under Grant[number 51575167]。
文摘This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor driver to rotate the motor.The torque distribution of motors is studied in this paper actually.Firstly,the model of the EMB system is established.Then the state observer is developed to estimate the vehicle states including the vehicle velocity and longitudinal force.Due to the fact that the EMB system is nonlinear and uncertain,a FSMC strategy based on wheel slip ratio is proposed,where both the normal and emergency braking conditions are taken into account.The equivalent control law of sliding mode controller is designed on the basis of the variation of the front axle and rear axle load during the brake process,while the switching control law is adjusted by the fuzzy corrector.The simulation results illustrate that the FSMC strategy has the superior performance,better adaptability to various types of roads,and shorter braking distance,as compared to PID control and traditional sliding mode control technologies.Finally,the hardware-in-loop(HIL)experimental results have exemplified the validation of the developed methodology.
基金Item Sponsored by National Key Fundamental Research Development Project of China(G1998061510)
文摘According to Maxwell electromagnetic field theory and magnetic vector potential integral equation,a mathematical model of LMF(Level Magnetic Field)for EMBR(Electromagnetic brake)was proposed,and the reliable software for LMF calculation was developed.The distribution of magnetic flux density given by numerical simulation shows that the magnetic flux density is greater in the magnet and magnetic leakage is observed in the gap.The magnetic flux density is uniform in horizontal plane and a peak is observed in vertical plane.Furthermore,the effects of electromagnetic and structural parameters on magnetic flux density were discussed.The relationship between magnetic flux,electromagnetic parameters and structural parameters is obtained by dimensional analysis,simulation experiment and least square method.
基金Project supported by the National Natural Science Foundation of China (Grant No.10675021)the New Century Excellent Talents in University of China,the Natural Science Foundation of Anhui Province of China (Grant No.090416224)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20103402110053)
文摘We investigate the Eulerian bond-cubic model on the square lattice by means of Monte Carlo simulations, using an efficient cluster algorithm and a finite-size scaling analysis. The critical points and four critical exponents of the model are determined for several values of n. Two of the exponents are fractal dimensions, which are obtained numerically for the first time. Our results are consistent with the Coulomb gas predictions for the critical O（n） branch for n 〈 2 and the results obtained by previous transfer matrix calculations. For n = 2, we find that the thermal exponent, the magnetic exponent and the fractal dimension of the largest critical Eulerian bond component are different from those of the critical 0（2） loop model. These results confirm that the cubic anisotropy is marginal at n = 2 but irrelevant for n〈2.
文摘Auditorium buildings are special structures needing much attention for it to function properly. Generally, consideration should be given to seating, sightlines, and acoustic requirements. In addition, the design should ensure performer-audience intimacy as much as possible. The focus of the study is to review design strategies for auditoria on the Kwame Nkrumah University of Science and Technology, Kumasi campus towards compliance and to develop solutions for improvements that will enhance the performance of 4 selected auditorium facilities. Case study, observation and measurements were the main strategies used. The results revealed that the approaches involved in auditorium designs are shape, volume, surface boundary dimensions and materials, stage, seating, foyers and sightlines. These parameters are grouped under acoustical, functional and programmatic parameters. Reverberation time calculated was high which indicated speech intelligibility problems, hence, improvement efforts were made to change the floor materials from polished tiles to carpeted floors, and high absorption wall claddings. In the process, the reverberation time was reduced from 1.47 - 2.23 to 0.84 - 1.73 for the studied buildings. The study recommends strict adherence to standards and guidelines, and for designers to have a keen focus on designing these special buildings. A renovation effort when undertaken, will lead to improvements in the performance of the selected buildings.
基金Supported by Japanese SMC Corporation with contract (No. 05-07)
文摘The servo system actuated by oscillating pneumatic cylinder for X-Y plate is a multi-variable nonlinear control system. Its mathematical model is established, and nonlinear factors are analyzed. Due to the existence of deadlock zone and the small damp of the pneumatic oscillating cylinder, it is likely to result in overshoot, and there is also certain steady-state error, so online modifying of proportion-integration-differentiation （PID） parameters is needed so as to achieve better control performance. Meanwhile considering the stability demand for long-term run, a fuzzy adaptive PID controller is designed. The result of hardware-inloop （HIL） test and real-time control experiment shows that the adaptive PID controller has desirable serfadaptability and robustness to external disturbance and to change of system parameters, and its control per- fonnance is better than that of traditional PID controllers.
基金supported by National Natural Science Foundation of ChinaState Grid Corporation Joint Fund for Smart Grid(No.U2066210).
文摘The development of low-carbon energy systems and renewable energy sources(RESs)are critical to solving the energy crisis around the world.However,renewable energy gen eration control strategies lead to fault characteristics such as fault current amplitude limitation and phase angle distortion.Focusing on large-scale renewable energy transmission lines,the sensitivity of traditional current differential protection and distance protection may be reduced,and there is even the risk of maloperation.Therefore,a suitable transmission line model is established,which considers the distributed capacitance.Af terward,a novel dynamic state estimation based protection(DSEBP)for large-scale renewable energy transmission lines is proposed.The proposed DSEBP adopts instantaneous measure ments and additional protection criteria to ensure the quick ac tion and reliability.Finally,faults are identified by checking the matching degree between the actual measurements and the es tablished transmission line model.The performance of the pro posed DSEBP is verified through PSCAD/EMTDC and realtime digital simulator(RTDS)hardware-in-loop tests.The re sults demonstrate that the proposed DSEBP can identify vari ous types of faults quickly and reliably.Meanwhile,the pro posed DSEBP has a better capability to withstand fault resis tance and disturbance.
基金Supported by National Social Science Foundation“Research on the Innovation and Promotion Strategy of China’s E-waste Recycling Model under the‘Internet+’Strategy”(18BGL182)。
文摘The popularization of smartphones and the acceleration of their replacement lead to a surge in mobile phone disposal.How to recycle waste mobile phones efficiently becomes a major problem in today’s society.The“Internet+”recycling mode is an effective way to solve this problem.The recycling process of waste mobile phones involves retailers,manufacturers,third parties and other recycling parts.Retailers have natural advantages compared with other parts because of their perfect sales network and logistics system.The system dynamics model for“Internet+”recycling of waste mobile phones dominated by retailers is constructed,and the Vensim software is used to simulate the influence of changes in two key factors in“Internet+”recycling environment:Annual operating cost of online platform and offline unit logistics cost on retailers’recycling volume and recycling profit.The results show that the investment of online platform operation cost is conducive to the increase of retailers’online waste mobile phone recycling volume and recycling profit,while the investment of offline logistics cost increases retailers’online waste mobile phone recycling volume,but reduces the recycling profit.
基金This work has been supported by the ANR DEAL(contract ANR-20-CE05-0016-01)This work has also been partially funded by Region Sud Provence-Alpes-Cote d’Azur via project AMULTI(2021_02918).
文摘In the paper,a novel self-learning energy management strategy(EMS)is proposed for fuel cell hybrid electric vehicles(FCHEV)to achieve the hydrogen saving and maintain the battery operation.In the EMS,it is proposed to approximate the EMS policy function with fuzzy inference system(FIS)and learn the policy parameters through policy gradient reinforcement learning(PGRL).Thus,a so-called Fuzzy REINFORCE algorithm is first proposed and studied for EMS problem in the paper.Fuzzy REINFORCE is a model-free method that the EMS agent can learn itself through interactions with environment,which makes it independent of model accuracy,prior knowledge,and expert experience.Meanwhile,to stabilize the training process,a fuzzy baseline function is adopted to approximate the value function based on FIS without affecting the policy gradient direction.More-over,the drawbacks of traditional reinforcement learning such as high computation burden,long convergence time,can also be overcome.The effectiveness of the proposed methods were verified by Hardware-in-Loop ex-periments.The adaptability of the proposed method to the changes of driving conditions and system states is also verified.
文摘Performance and energy consumption of high performance computing （HPC） interconnection networks have a great significance in the whole supercomputer, and building up HPC interconnection network simulation plat- form is very important for the research on HPC software and hardware technologies. To effectively evaluate the per- formance and energy consumption of HPC interconnection networks, this article designs and implements a detailed and clock-driven HPC interconnection network simulation plat- form, called HPC-NetSim. HPC-NetSim uses application- driven workloads and inherits the characteristics of the de- tailed and flexible cycle-accurate network simulator. Besides, it offers a large set of configurable network parameters in terms of topology and routing, and supports router＇s on/off states. We compare the simulated execution time with the real execution time of Tianhe-2 subsystem and the mean error is only 2.7%. In addition, we simulate the network behaviors with different network structures and low-power modes. The results are also consistent with the theoretical analyses.
