This research work investigated comparative studies of expert system design and control of crude oil distillation column (CODC) using artificial neural networks based Monte Carlo (ANNBMC) simulation of random processe...This research work investigated comparative studies of expert system design and control of crude oil distillation column (CODC) using artificial neural networks based Monte Carlo (ANNBMC) simulation of random processes and artificial neural networks (ANN) model which were validated using experimental data obtained from functioning crude oil distillation column of Port-Harcourt Refinery, Nigeria by MATLAB computer program. Ninety percent (90%) of the experimental data sets were used for training while ten percent (10%) were used for testing the networks. The maximum relative errors between the experimental and calculated data obtained from the output variables of the neural network for CODC design were 1.98 error % and 0.57 error % when ANN only and ANNBMC were used respectively while their respective values for the maximum relative error were 0.346 error % and 0.124 error % when they were used for the controller prediction. Larger number of iteration steps of below 2500 and 5000 were required to achieve convergence of less than 10-7?for the training error using ANNBMC for both the design of the CODC and controller respectively while less than 400 and 700 iteration steps were needed to achieve convergence of 10-4?using ANN only. The linear regression analysis performed revealed the minimum and maximum prediction accuracies to be 80.65% and 98.79%;and 98.38% and 99.98% when ANN and ANNBMC were used for the CODC design respectively. Also, the minimum and maximum prediction accuracies were 92.83% and 99.34%;and 98.89% and 99.71% when ANN and ANNBMC were used for the CODC controller respectively as both methodologies have excellent predictions. Hence, artificial neural networks based Monte Carlo simulation is an effective and better tool for the design and control of crude oil distillation column.展开更多
The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation...The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation, the thermal design of ECU for electronic unit pump （EUP） fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time展开更多
Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power ...Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power supply for engineering application was designed which reduced power wastage by adopting soft switch technology; lessened its volume to satisfy micromation when adopting the planar transformer and improved its response character- istic by choosing an assistant discharging circuit. Simultaneously, a simulation analysis has been carried out. As results, the output voltage of this high voltage power supply is 5 kV, and the voltage can be continuously regulated and the voltage ripple is only 0. 7 %, so the requirement of stability is also achieved.展开更多
When designing a complex mechatronics system,such as high speed trains,it is relatively difficult to effectively simulate the entire system's dynamic behaviors because it involves multi-disciplinary subsystems.Cur...When designing a complex mechatronics system,such as high speed trains,it is relatively difficult to effectively simulate the entire system's dynamic behaviors because it involves multi-disciplinary subsystems.Currently,a most practical approach for multi-disciplinary simulation is interface based coupling simulation method,but it faces a twofold challenge:spatial and time unsynchronizations among multi-directional coupling simulation of subsystems.A new collaborative simulation method with spatiotemporal synchronization process control is proposed for coupling simulating a given complex mechatronics system across multiple subsystems on different platforms.The method consists of 1)a coupler-based coupling mechanisms to define the interfacing and interaction mechanisms among subsystems,and 2)a simulation process control algorithm to realize the coupling simulation in a spatiotemporal synchronized manner.The test results from a case study show that the proposed method 1)can certainly be used to simulate the sub-systems interactions under different simulation conditions in an engineering system,and 2)effectively supports multi-directional coupling simulation among multi-disciplinary subsystems.This method has been successfully applied in China high speed train design and development processes,demonstrating that it can be applied in a wide range of engineering systems design and simulation with improved efficiency and effectiveness.展开更多
A movement law of laser beam facula is designed for the injection trajectory of hyper-ve- locity kinetic energy missile to eliminate the influence of motor exhaust smoke on laser signal trans mission. Taking guidance...A movement law of laser beam facula is designed for the injection trajectory of hyper-ve- locity kinetic energy missile to eliminate the influence of motor exhaust smoke on laser signal trans mission. Taking guidance loop of hyper velocity kinetic energy missile as plant, a closed loop control system with desired step response characteristics is constructed and the movement law of laser beam facula for the missile injection trajectory is designed based on the output signal of the closed loop controller under a step input. Six degree of freedom trajectory simulations show that by the guidance of the laser beam facula moving with designed law, the missile can finish transition from the initial trajectory to a stable tracking trajectory without overshoot within the required time.展开更多
Based on the character of the modular self-reconfigurable （MSR） robot, a novel homogeneous and lattice MSR robot, M-Cubes, was designed. Each module unit of the robot has 12 freedoms and is composed of six rotary jo...Based on the character of the modular self-reconfigurable （MSR） robot, a novel homogeneous and lattice MSR robot, M-Cubes, was designed. Each module unit of the robot has 12 freedoms and is composed of six rotary joints and one cubic link. An attached/detached mechanism was designed on the rotary joints. A novel space transmitting system was placed on the inner portion of the cubic link. A motor separately transmitted torque to the six joints which were distributed equally on six surfaces of the cubic link. The example of a basic motion for the module was demonstrated. The result shows that the robot is concise and compact in structure, highly efficient in transmission, credible in connecting, and simple in controlling. At the same time, a simulator is developed to graphically design the system configuration, the reconfiguration process and the motion of cluster modules. The character of local action for the cellular automata （CA） is utilized. Each module is simplified as a cell. The transition rules of the CA are developed to combine with the genetic algorithm （GA） and applied to each module to accomplish distributed control. Simulation proves that the method is effective and feasible.展开更多
The Microgravity Active vibration Isolation System(MAIS),which was onboard China’s first cargo-spacecraft Tianzhou-1 launched on April 20,2017,aims to provide high-level microgravity at an order of 10^(-5)–10^(-6)g ...The Microgravity Active vibration Isolation System(MAIS),which was onboard China’s first cargo-spacecraft Tianzhou-1 launched on April 20,2017,aims to provide high-level microgravity at an order of 10^(-5)–10^(-6)g for specific scientific experiments.MAIS is mainly composed of a stator and a floater,and payloads are mounted on the floater.Sensing relative motion with respect to the stator fixed on the spacecraft,the floater is isolated from vibration on the stator via control forces and torques generated by electromagnetic actuators.This isolation results in a high-level microgravity environment.Before MAIS was launched into space,its control performance had been simulated on computers and tested by air-bearing platform levitation and aircraft parabolic flight.This article first presents an overview of the MAIS’s hardware system,particularly system structure,measurement sensors,and control actuators.Its system dynamics,state estimation,and control laws are then discussed,followed by the results of computer simulation and engineering tests,including the test of the six-degree-of-freedom motion by aircraft parabolic flight.Simulation and test results verify the accuracy of the control strategy design,effectiveness of the control algorithms,and performance of the entire control system,paving the way for operation of MAIS in space.This article also presents the steps recommended for the control performance simulation and tests of MAIS-like devices.These devices are expected to be used on China’s Space Station for various scientific experiments that require a high-level microgravity environment.展开更多
A difficult but important problem in optimal control theory is the design of an optimal feedback control, i.e., the design of an optimal control as function of the phase (state) coordinates [1,2]. This problem can be ...A difficult but important problem in optimal control theory is the design of an optimal feedback control, i.e., the design of an optimal control as function of the phase (state) coordinates [1,2]. This problem can be solved not often. We study here the autonomous nonlinear system of second order in general form. The constraints imposed on the control input can depend on the phase (state) coordinates of the system. The goal of the control is to maximize or minimize one phase coordinate of the considered system while other takes a prescribed in advance value. In the literature, optimal control problems for the systems of second order are most frequently associated with driving both phase coordinates to a prescribed in advance state. In this statement of the problem, the optimal control feedback can be designed only for special kind of systems. In our statement of the problem, an optimal control can be designed as function of the state coordinates for more general kind of the systems. The problem of maximization or minimization of the swing amplitude is considered explicitly as an example. Simulation results are presented.展开更多
In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling perfor...In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling performances of the aircraft. The eigenvalue sen sitivity approach is employed to study the effect of coupling parameters on system stability and gain sensitivity approach is used to direct the reduced states feedback suboptimal control system design. Simulation results show that the integrated flight propulsion control system designed by sensitivity approaches is of good performance.展开更多
In this modern era, power generation seems to be a very demanding factor. New models and methods have been proposed to derive from various natural and manmade resources. In such instances, this paper gives a detailed ...In this modern era, power generation seems to be a very demanding factor. New models and methods have been proposed to derive from various natural and manmade resources. In such instances, this paper gives a detailed report on the power generation from Micro Turbines. Micro turbine plays a very important role in electric power generation. Especially they are used in the combined cycle process power plants. The parameters of Rowen’s model 265-MW single shaftheavy duty gas turbines which are used in dynamic studies are estimated in this paper using the operational and performance data. These data are also used to briefly explain the extraction of parameters of the used model. Micro turbine parameters are approximated using simple thermodynamics assumptions. Micro turbine power generation seems to be an uprising and a promising source and an exact design with a perfect model is capable of producing the highest efficiency. Thus this paper is proposed on the aspects of social awareness to elaborate the control design of Micro Turbine Power Generation System. The parameters of micro turbine models are derived and the results of several simulated tests using Matlab/Simulink are presented.展开更多
This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking...This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking capacity for systems with uncertainties and disturbances. First, SMC discrete equivalent control law is designed on the basis of the nominal model of the system and the adaptive exponential reaching law, and subsequently, stability of the algorithm is analyzed. Second, RBF network is used to f...展开更多
As for the complex operational tasks in the unstructured environment with narrow workspace and numerous obstacles,the traditional robots cannot accomplish these mentioned complex operational tasks and meet the dexteri...As for the complex operational tasks in the unstructured environment with narrow workspace and numerous obstacles,the traditional robots cannot accomplish these mentioned complex operational tasks and meet the dexterity demands.The hyper-redundant bionic robots can complete complex tasks in the unstructured environments by simulating the motion characteristics of the elephant’s trunk and octopus tentacles.Compared with traditional robots,the hyper-redundant bionic robots can accomplish complex tasks because of their flexible structure.A hyper-redundant elephant’s trunk robot(HRETR)with an open structure is developed in this paper.The content includes mechanical structure design,kinematic analysis,virtual prototype simulation,control system design,and prototype building.This design is inspired by the flexible motion of an elephant’s trunk,which is expansible and is composed of six unit modules,namely,3UPS-PS parallel in series.First,the mechanical design of the HRETR is completed according to the motion characteristics of an elephant’s trunk and based on the principle of mechanical bionic design.After that,the backbone mode method is used to establish the kinematic model of the robot.The simulation software SolidWorks and ADAMS are combined to analyze the kinematic characteristics when the trajectory of the end moving platform of the robot is assigned.With the help of ANSYS,the static stiffness of each component and the whole robot is analyzed.On this basis,the materials of the weak parts of the mechanical structure and the hardware are selected reasonably.Next,the extensible structures of software and hardware control system are constructed according to the modular and hierarchical design criteria.Finally,the prototype is built and its performance is tested.The proposed research provides a method for the design and development for the hyper-redundant bionic robot.展开更多
The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our prev...The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our previous work,a novel industrial p-xylene oxidation reactor model using the free radical mechanism based kinetics has been developed.However,the disturbances such as production rate change,feed composition variability and reactor temperature changes widely exist in the industry process.In this paper,dynamic simulation of the PX oxidation reactor was designed by Aspen Dynamics and used to develop an effective plantwide control structure,which was capable of effectively handling the disturbances in the load and the temperature of the reactor.Step responses of the control structure to the disturbances were shown and served as the foundation of the smooth operation and advanced control strategy of this process in our future work.展开更多
Landing dynamic simulation and landing-gear optimization design are used to improve the landing-gear design for a flexible airplane. Landing response is simulated by using velocity-squared damping, polytropic exponent...Landing dynamic simulation and landing-gear optimization design are used to improve the landing-gear design for a flexible airplane. Landing response is simulated by using velocity-squared damping, polytropic exponential air-compression spring, tire force power function characteristics, and an equivalent three-mass system.Optimization of landing-gear parameters is performed considering the maximum displacement of the landing-gear shock stroke, the maximum landing-gear force and the maximum deformation of the wingtip in the landing impact. Resutls show that landing-gear design parameters have an important influence on the structural flexibility of the airplane. And the landing performance of the landing-gear can be improved by the optimized metering pin type landing-gear.展开更多
This paper intends to provide theoretical basis for matching design of hydraulic load simulator （HLS） with aerocraft actuator in hardware-in-loop test, which is expected to help actuator designers overcome the obsta...This paper intends to provide theoretical basis for matching design of hydraulic load simulator （HLS） with aerocraft actuator in hardware-in-loop test, which is expected to help actuator designers overcome the obstacles in putting forward appropriate requirements of HLS. Traditional research overemphasizes the optimization of parameters and methods for HLS controllers. It lacks deliberation because experimental results and project experiences indicate different ultimate performance of a specific HLS. When the actuator paired with this HLS is replaced, the dynamic response and tracing precision of this HLS also change, and sometimes the whole system goes so far as to lose control. Based on the influence analysis of the preceding phenomena, a theory about matching design of aerocraft actuator with HLS is presented, together with two paired new concepts of ＂Standard Actuator＂ and ＂Standard HLS＂. Further research leads to seven important conclusions of matching design, which suggest that appropriate stiffness and output torque of HLS should be carefully designed and chosen for an actuator. Simulation results strongly support that the proposed principle of matching design can be anticipated to be one of the design criteria for HLS, and successfully used to explain experimental phenomena and project experiences.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
Substantially lightweight brake discs with high wear resistance are highly desirable in the automotive industry.This paper presents an investigation of the precision-engineering design and development of automotive br...Substantially lightweight brake discs with high wear resistance are highly desirable in the automotive industry.This paper presents an investigation of the precision-engineering design and development of automotive brake discs using nonhomogeneous Al/SiC metal-matrixcomposite materials.The design and development are based on modeling and analysis following stringent precision-engineering principles,i.e.,brake-disc systems that operate repeatably and stably over time as enabled by precision-engineering design.The design and development are further supported by tribological experimental testing and finite-element simulations.The results show the industrial feasibility of the innovative design approach and the application merits of using advanced metal-matrix-composite materials for next-generation automotive and electric vehicles.展开更多
This paper presents a new design of CADEL,a cable-driven elbow-assisting device,with light weighting and control improvements.The new device design is appropriate to be more portable and user-oriented solution,present...This paper presents a new design of CADEL,a cable-driven elbow-assisting device,with light weighting and control improvements.The new device design is appropriate to be more portable and user-oriented solution,presenting additional facilities with respect to the original design.One of potential benefits of improved portability can be envisaged in the possibility of house and hospital usage keeping social distancing while allowing rehabilitation treatments even during a pandemic spread.Specific attention has been devoted to design main mechatronic components by developing specific kinematics models.The design process includes an implementation of specific control hardware and software.The kinematic model of the new design is formulated and features are evaluated through numerical simulations and experimental tests.An evaluation from original design highlights the proposed improvements mainly in terms of comfort,portability and user-oriented operation.展开更多
文摘This research work investigated comparative studies of expert system design and control of crude oil distillation column (CODC) using artificial neural networks based Monte Carlo (ANNBMC) simulation of random processes and artificial neural networks (ANN) model which were validated using experimental data obtained from functioning crude oil distillation column of Port-Harcourt Refinery, Nigeria by MATLAB computer program. Ninety percent (90%) of the experimental data sets were used for training while ten percent (10%) were used for testing the networks. The maximum relative errors between the experimental and calculated data obtained from the output variables of the neural network for CODC design were 1.98 error % and 0.57 error % when ANN only and ANNBMC were used respectively while their respective values for the maximum relative error were 0.346 error % and 0.124 error % when they were used for the controller prediction. Larger number of iteration steps of below 2500 and 5000 were required to achieve convergence of less than 10-7?for the training error using ANNBMC for both the design of the CODC and controller respectively while less than 400 and 700 iteration steps were needed to achieve convergence of 10-4?using ANN only. The linear regression analysis performed revealed the minimum and maximum prediction accuracies to be 80.65% and 98.79%;and 98.38% and 99.98% when ANN and ANNBMC were used for the CODC design respectively. Also, the minimum and maximum prediction accuracies were 92.83% and 99.34%;and 98.89% and 99.71% when ANN and ANNBMC were used for the CODC controller respectively as both methodologies have excellent predictions. Hence, artificial neural networks based Monte Carlo simulation is an effective and better tool for the design and control of crude oil distillation column.
文摘The high working junction temperature of power component is the most common reason of its failure. So the thermal design is of vital importance in electronic control unit （ECU） design. By means of circuit simulation, the thermal design of ECU for electronic unit pump （EUP） fuel system is applied. The power dissipation model of each power component in the ECU is created and simulated. According to the analyses of simulation results, the factors which affect the power dissipation of components are analyzed. Then the ways for reducing the power dissipation of power components are carried out. The power dissipation of power components at different engine state is calculated and analyzed. The maximal power dissipation of each power component in all possible engine state is also carried out based on these simulations. A cooling system is designed based on these studies. The tests show that the maximum total power dissipation of ECU drops from 43.2 W to 33.84 W after these simulations and optimizations. These applications of simulations in thermal design of ECU can greatly increase the quality of the design, save the design cost and shorten design time
基金supported by the National Natural Science Founda-tion under Grant No. 50771089 and No.10802029
文摘Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power supply for engineering application was designed which reduced power wastage by adopting soft switch technology; lessened its volume to satisfy micromation when adopting the planar transformer and improved its response character- istic by choosing an assistant discharging circuit. Simultaneously, a simulation analysis has been carried out. As results, the output voltage of this high voltage power supply is 5 kV, and the voltage can be continuously regulated and the voltage ripple is only 0. 7 %, so the requirement of stability is also achieved.
基金Supported by National High Technology Research and Development Program of China(863 Program,Grant No.2015AA043701-02)
文摘When designing a complex mechatronics system,such as high speed trains,it is relatively difficult to effectively simulate the entire system's dynamic behaviors because it involves multi-disciplinary subsystems.Currently,a most practical approach for multi-disciplinary simulation is interface based coupling simulation method,but it faces a twofold challenge:spatial and time unsynchronizations among multi-directional coupling simulation of subsystems.A new collaborative simulation method with spatiotemporal synchronization process control is proposed for coupling simulating a given complex mechatronics system across multiple subsystems on different platforms.The method consists of 1)a coupler-based coupling mechanisms to define the interfacing and interaction mechanisms among subsystems,and 2)a simulation process control algorithm to realize the coupling simulation in a spatiotemporal synchronized manner.The test results from a case study show that the proposed method 1)can certainly be used to simulate the sub-systems interactions under different simulation conditions in an engineering system,and 2)effectively supports multi-directional coupling simulation among multi-disciplinary subsystems.This method has been successfully applied in China high speed train design and development processes,demonstrating that it can be applied in a wide range of engineering systems design and simulation with improved efficiency and effectiveness.
文摘A movement law of laser beam facula is designed for the injection trajectory of hyper-ve- locity kinetic energy missile to eliminate the influence of motor exhaust smoke on laser signal trans mission. Taking guidance loop of hyper velocity kinetic energy missile as plant, a closed loop control system with desired step response characteristics is constructed and the movement law of laser beam facula for the missile injection trajectory is designed based on the output signal of the closed loop controller under a step input. Six degree of freedom trajectory simulations show that by the guidance of the laser beam facula moving with designed law, the missile can finish transition from the initial trajectory to a stable tracking trajectory without overshoot within the required time.
文摘Based on the character of the modular self-reconfigurable （MSR） robot, a novel homogeneous and lattice MSR robot, M-Cubes, was designed. Each module unit of the robot has 12 freedoms and is composed of six rotary joints and one cubic link. An attached/detached mechanism was designed on the rotary joints. A novel space transmitting system was placed on the inner portion of the cubic link. A motor separately transmitted torque to the six joints which were distributed equally on six surfaces of the cubic link. The example of a basic motion for the module was demonstrated. The result shows that the robot is concise and compact in structure, highly efficient in transmission, credible in connecting, and simple in controlling. At the same time, a simulator is developed to graphically design the system configuration, the reconfiguration process and the motion of cluster modules. The character of local action for the cellular automata （CA） is utilized. Each module is simplified as a cell. The transition rules of the CA are developed to combine with the genetic algorithm （GA） and applied to each module to accomplish distributed control. Simulation proves that the method is effective and feasible.
基金The authors gratefully acknowledge DLR for providing us the opportunity to attend the 27th parabolic flight campaign and Novespace for the support for the test of MAIS by the Airbus A310 ZERO-GThe authors would also like to thank Weijia Ren,Xiaoru Sang,Shimeng Lv,Peng Yang,Yu-e Gao,Lingcai Song,Mengxi Yu,Boqi Kang,Yanlin Zhou,and Anping Wang,who have contributed significantly to the MAIS project.
文摘The Microgravity Active vibration Isolation System(MAIS),which was onboard China’s first cargo-spacecraft Tianzhou-1 launched on April 20,2017,aims to provide high-level microgravity at an order of 10^(-5)–10^(-6)g for specific scientific experiments.MAIS is mainly composed of a stator and a floater,and payloads are mounted on the floater.Sensing relative motion with respect to the stator fixed on the spacecraft,the floater is isolated from vibration on the stator via control forces and torques generated by electromagnetic actuators.This isolation results in a high-level microgravity environment.Before MAIS was launched into space,its control performance had been simulated on computers and tested by air-bearing platform levitation and aircraft parabolic flight.This article first presents an overview of the MAIS’s hardware system,particularly system structure,measurement sensors,and control actuators.Its system dynamics,state estimation,and control laws are then discussed,followed by the results of computer simulation and engineering tests,including the test of the six-degree-of-freedom motion by aircraft parabolic flight.Simulation and test results verify the accuracy of the control strategy design,effectiveness of the control algorithms,and performance of the entire control system,paving the way for operation of MAIS in space.This article also presents the steps recommended for the control performance simulation and tests of MAIS-like devices.These devices are expected to be used on China’s Space Station for various scientific experiments that require a high-level microgravity environment.
文摘A difficult but important problem in optimal control theory is the design of an optimal feedback control, i.e., the design of an optimal control as function of the phase (state) coordinates [1,2]. This problem can be solved not often. We study here the autonomous nonlinear system of second order in general form. The constraints imposed on the control input can depend on the phase (state) coordinates of the system. The goal of the control is to maximize or minimize one phase coordinate of the considered system while other takes a prescribed in advance value. In the literature, optimal control problems for the systems of second order are most frequently associated with driving both phase coordinates to a prescribed in advance state. In this statement of the problem, the optimal control feedback can be designed only for special kind of systems. In our statement of the problem, an optimal control can be designed as function of the state coordinates for more general kind of the systems. The problem of maximization or minimization of the swing amplitude is considered explicitly as an example. Simulation results are presented.
文摘In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling performances of the aircraft. The eigenvalue sen sitivity approach is employed to study the effect of coupling parameters on system stability and gain sensitivity approach is used to direct the reduced states feedback suboptimal control system design. Simulation results show that the integrated flight propulsion control system designed by sensitivity approaches is of good performance.
文摘In this modern era, power generation seems to be a very demanding factor. New models and methods have been proposed to derive from various natural and manmade resources. In such instances, this paper gives a detailed report on the power generation from Micro Turbines. Micro turbine plays a very important role in electric power generation. Especially they are used in the combined cycle process power plants. The parameters of Rowen’s model 265-MW single shaftheavy duty gas turbines which are used in dynamic studies are estimated in this paper using the operational and performance data. These data are also used to briefly explain the extraction of parameters of the used model. Micro turbine parameters are approximated using simple thermodynamics assumptions. Micro turbine power generation seems to be an uprising and a promising source and an exact design with a perfect model is capable of producing the highest efficiency. Thus this paper is proposed on the aspects of social awareness to elaborate the control design of Micro Turbine Power Generation System. The parameters of micro turbine models are derived and the results of several simulated tests using Matlab/Simulink are presented.
文摘This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking capacity for systems with uncertainties and disturbances. First, SMC discrete equivalent control law is designed on the basis of the nominal model of the system and the adaptive exponential reaching law, and subsequently, stability of the algorithm is analyzed. Second, RBF network is used to f...
基金Supported by National Natural Science Foundation of China(Grant No.51375288)Science and Technology Program of Guangdong Province of China(Grant No.2020ST004)+1 种基金Department of Education of Guangdong Province of China(Grant No.2017KZDXM036and Special Project for Science and Technology Innovation Team of Foshan City of China(Grant No.2018IT100052).
文摘As for the complex operational tasks in the unstructured environment with narrow workspace and numerous obstacles,the traditional robots cannot accomplish these mentioned complex operational tasks and meet the dexterity demands.The hyper-redundant bionic robots can complete complex tasks in the unstructured environments by simulating the motion characteristics of the elephant’s trunk and octopus tentacles.Compared with traditional robots,the hyper-redundant bionic robots can accomplish complex tasks because of their flexible structure.A hyper-redundant elephant’s trunk robot(HRETR)with an open structure is developed in this paper.The content includes mechanical structure design,kinematic analysis,virtual prototype simulation,control system design,and prototype building.This design is inspired by the flexible motion of an elephant’s trunk,which is expansible and is composed of six unit modules,namely,3UPS-PS parallel in series.First,the mechanical design of the HRETR is completed according to the motion characteristics of an elephant’s trunk and based on the principle of mechanical bionic design.After that,the backbone mode method is used to establish the kinematic model of the robot.The simulation software SolidWorks and ADAMS are combined to analyze the kinematic characteristics when the trajectory of the end moving platform of the robot is assigned.With the help of ANSYS,the static stiffness of each component and the whole robot is analyzed.On this basis,the materials of the weak parts of the mechanical structure and the hardware are selected reasonably.Next,the extensible structures of software and hardware control system are constructed according to the modular and hierarchical design criteria.Finally,the prototype is built and its performance is tested.The proposed research provides a method for the design and development for the hyper-redundant bionic robot.
基金Supported by the Major State Basic Research Development Program of China(2012CB720500)the National Natural Science Foundation of China(U1162202)+2 种基金the Shanghai Second Polytechnic University Key Discipline Construction(4th term)-Control Theory&Control Engineering(XXKPY1308)the Cultivation Program of Young Teachers in Colleges and Universities of Shanghai(ZZegdl4013)the School Foundation of Shanghai Second Polytechnic University(EGD14XQD02)
文摘The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our previous work,a novel industrial p-xylene oxidation reactor model using the free radical mechanism based kinetics has been developed.However,the disturbances such as production rate change,feed composition variability and reactor temperature changes widely exist in the industry process.In this paper,dynamic simulation of the PX oxidation reactor was designed by Aspen Dynamics and used to develop an effective plantwide control structure,which was capable of effectively handling the disturbances in the load and the temperature of the reactor.Step responses of the control structure to the disturbances were shown and served as the foundation of the smooth operation and advanced control strategy of this process in our future work.
文摘Landing dynamic simulation and landing-gear optimization design are used to improve the landing-gear design for a flexible airplane. Landing response is simulated by using velocity-squared damping, polytropic exponential air-compression spring, tire force power function characteristics, and an equivalent three-mass system.Optimization of landing-gear parameters is performed considering the maximum displacement of the landing-gear shock stroke, the maximum landing-gear force and the maximum deformation of the wingtip in the landing impact. Resutls show that landing-gear design parameters have an important influence on the structural flexibility of the airplane. And the landing performance of the landing-gear can be improved by the optimized metering pin type landing-gear.
基金the Aviation Science Foundation (No. 20110951009) of ChinaNational Nature Science Foundation for Distinguished Young Scholars ( No. 50825502 ) of China for the financial support
文摘This paper intends to provide theoretical basis for matching design of hydraulic load simulator （HLS） with aerocraft actuator in hardware-in-loop test, which is expected to help actuator designers overcome the obstacles in putting forward appropriate requirements of HLS. Traditional research overemphasizes the optimization of parameters and methods for HLS controllers. It lacks deliberation because experimental results and project experiences indicate different ultimate performance of a specific HLS. When the actuator paired with this HLS is replaced, the dynamic response and tracing precision of this HLS also change, and sometimes the whole system goes so far as to lose control. Based on the influence analysis of the preceding phenomena, a theory about matching design of aerocraft actuator with HLS is presented, together with two paired new concepts of ＂Standard Actuator＂ and ＂Standard HLS＂. Further research leads to seven important conclusions of matching design, which suggest that appropriate stiffness and output torque of HLS should be carefully designed and chosen for an actuator. Simulation results strongly support that the proposed principle of matching design can be anticipated to be one of the design criteria for HLS, and successfully used to explain experimental phenomena and project experiences.
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Substantially lightweight brake discs with high wear resistance are highly desirable in the automotive industry.This paper presents an investigation of the precision-engineering design and development of automotive brake discs using nonhomogeneous Al/SiC metal-matrixcomposite materials.The design and development are based on modeling and analysis following stringent precision-engineering principles,i.e.,brake-disc systems that operate repeatably and stably over time as enabled by precision-engineering design.The design and development are further supported by tribological experimental testing and finite-element simulations.The results show the industrial feasibility of the innovative design approach and the application merits of using advanced metal-matrix-composite materials for next-generation automotive and electric vehicles.
文摘This paper presents a new design of CADEL,a cable-driven elbow-assisting device,with light weighting and control improvements.The new device design is appropriate to be more portable and user-oriented solution,presenting additional facilities with respect to the original design.One of potential benefits of improved portability can be envisaged in the possibility of house and hospital usage keeping social distancing while allowing rehabilitation treatments even during a pandemic spread.Specific attention has been devoted to design main mechatronic components by developing specific kinematics models.The design process includes an implementation of specific control hardware and software.The kinematic model of the new design is formulated and features are evaluated through numerical simulations and experimental tests.An evaluation from original design highlights the proposed improvements mainly in terms of comfort,portability and user-oriented operation.
