Sensor plays an important role in robotics. Sensors are used to determine the current state of the system. Robotic applications demand sensors with high degrees of repeatability, precision, and reliability. Flex senso...Sensor plays an important role in robotics. Sensors are used to determine the current state of the system. Robotic applications demand sensors with high degrees of repeatability, precision, and reliability. Flex sensor is such a device, which accomplish the above task with great degree of accuracy. The pick and place operation of the robotics arm can be efficiently controlled using micro controller programming. This designed work is an educational based concept as robotic control is an exciting and high challenge research work in recent year.展开更多
This paper discusses the design and implementation of single phase PWM inverter using 8051 microcontrol-ler. The main features of 8051 based PWM inverter are simpler design, low cost, maximum range of voltage control ...This paper discusses the design and implementation of single phase PWM inverter using 8051 microcontrol-ler. The main features of 8051 based PWM inverter are simpler design, low cost, maximum range of voltage control and compact in size. The designed PWM inverter is tested on various AC loads like AC motor and intensity control of incandescent lamp in a closed loop environment.展开更多
Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity ...Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.展开更多
A 32 kbit OTP(one-time programmable)memory for MCUs(micro-controller units)used in remote controllers was designed.This OTP memory is used for program and data storage.It is required to apply 5.5V to BL(bit-line)and 1...A 32 kbit OTP(one-time programmable)memory for MCUs(micro-controller units)used in remote controllers was designed.This OTP memory is used for program and data storage.It is required to apply 5.5V to BL(bit-line)and 11V to WL(word-line)for a OTP cell of 0.35μm ETOX(EEPROM tunnel oxide)type by MagnaChip.We use 5V transistors on column data paths to reduce the area of column data paths since they require small areas.In addition,we secure device reliability by using HV(high-voltage)transistors in the WL driver.Furthermore,we change from a static logic to a dynamic logic used for the WL driver in the core circuit.Also,we optimize the WD(write data)switch circuit.Thus,we can implement them with a small-area design.In addition,we implement the address predecoder with a small-area logic circuit.The area of the designed 32 kbit OTP with 5V and HV devices is 674.725μm×258.75μm(=0.1745mm2)and is 56.3% smaller than that using 3.3V devices.展开更多
Some disperse dyes were microencapsulated by means of in- situ polymerization. These microencapsulated disperse dyes was extracted respectively by ethanol under certain conditions. The controlled-release properties of...Some disperse dyes were microencapsulated by means of in- situ polymerization. These microencapsulated disperse dyes was extracted respectively by ethanol under certain conditions. The controlled-release properties of disperse dyes through the shell of microcapsules were measured by spectrophotometer. According to the results, it was drawn that the type of disperse dyes, the auxiliaries contained in disperse dyes, the quantity of system controlling medium used and the core/shell ratio of microcapsules play important roles in controlling the release properties of microcapsules. The different controlled- release properties of microcapsules, which were prepared under given conditions, however, would in turn influence the performance of microcapsules in multiple-transfer printing.展开更多
Magneto-rheological elastomers (MILEs) are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoel...Magneto-rheological elastomers (MILEs) are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoelastic material is characterized by a complex modulus dependent on vibration frequency and controllable by external magnetic fields. Frequency-domain solution methods for stochastic micro-vibration response analysis of the MRE-based structural systems are developed to derive the system frequency-response function matrices and the expressions of the velocity response spectrum. With these equations, the root-mean-square (RMS) velocity responses in terms of the one-third octave frequency band spectrum can be calculated. Further, the optimization problem of the complex moduli of the MRE cores is defined by minimizing the velocity response spectra and the RMS velocity responses through altering the applied magnetic fields. Simulation results illustrate the influences of MRE parameters on the RMS velocity responses and the high response reduction capacities of the MRE-based structures. In addition, the developed frequency-domain analysis methods are applicable to sandwich beam structures with arbitrary cores characterized by complex shear moduli under stochastic excitations described by power spectral density functions, and are valid for a wide frequency range.展开更多
The effects of the micro-ramps on supersonic turbulent flow over a forward-facing step(FFS) was experimentally investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scatt...The effects of the micro-ramps on supersonic turbulent flow over a forward-facing step(FFS) was experimentally investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering(NPLS)and particle image velocimetry(PIV) techniques. High spatiotemporal resolution images and velocity fields of supersonic flow over the testing model were captured. The fine structures and their spatial evolutionary characteristics without and with the micro-ramps were revealed and compared. The large-scale structures generated by the micro-ramps can survive the downstream FFS flowfield. The micro-ramps control on the flow separation and the separation shock unsteadiness was investigated by PIV results. With the micro-ramps, the reduction in the range of the reversal flow zone in streamwise direction is 50% and the turbulence intensity is also reduced. Moreover, the reduction in the average separated region and in separation shock unsteadiness are 47% and 26%, respectively. The results indicate that the micro-ramps are effective in reducing the flow separation and the separation shock unsteadiness.展开更多
The continuous cooling transformation of hot deformation austenite austenite of test steel and the effect of different processing schedules of controlled rolling and controlled cooling on the strength and ductility ha...The continuous cooling transformation of hot deformation austenite austenite of test steel and the effect of different processing schedules of controlled rolling and controlled cooling on the strength and ductility have been studied. The theory and the experiment base are presented for controlled rolling and controlled cooling of the SBL micro alloyed engineering steel.展开更多
Microgrids have been proposed in order to improve reliability and stability of electrical system and to ensure power quality of grid. Microgrid consists of low voltage distribution systems with distributed energy reso...Microgrids have been proposed in order to improve reliability and stability of electrical system and to ensure power quality of grid. Microgrid consists of low voltage distribution systems with distributed energy resources, such as wind turbine and photovoltaic power systems, together with storage devices. It is essential to protect a micro grid in both the grid-connected and the islanded mode of operation against all different types of faults. This paper describes micro grid protection and safety concept with central control and monitoring unit where multifunctional intelligent digital relay could be used. This central control & monitoring infrastructure is used for adaptive relay settings strategy for micro grid protection. Also operational safety design concept and fault mitigation technique is proposed to ensure confidence in protection system.展开更多
This paper presents the design and implementation of an energy management system (EMS) with wavelet transform and fuzzy control for a residential micro-grid. The hybrid system in this paper consists of a wind turbin...This paper presents the design and implementation of an energy management system (EMS) with wavelet transform and fuzzy control for a residential micro-grid. The hybrid system in this paper consists of a wind turbine generator, photovoltaic (PV) panels, an electric vehicle (EV), and a super capacitor (SC), which is able to connect or disconnect to the main grid. The control strategy is responsible for compensating the difference between the generated power by the wind and solar generators and the demanded power by the loads. Wavelet transform decomposes the power difference into a smoothed component and a fast fluctuated component. The command approach used for fuzzy logic rules considers the state of charging (SOC) of EV, renewable production, and the load demand as parameters. Furthermore, the command rules are developed in order to ensure a reliable grid when taking into account the EV battery protection to decide the output power of the EV. The model of the hybrid system is developed in detail under Matlab/Simulink software environment.展开更多
The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were ...The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were studied and three kinds of phenolic emulsifiers were prepared without catalyst in ethanol. The performance was researched that 2-({2-[2-(2-Amino-ethylamino)-ethylamino]-ethyl-amino}-methyl)-4- nonyl-phenol (abbreviated as TETA) could be used in micro-surface. With addition of 0.5 % demulsifier, the mixing time was extended to 120 seconds obviously, and the cohesion torque (60 min) was 2.8 N*m, which satisfied the opening traffic time shorter than 1 h. The wet track abrasion (6 d) was lower than 807 g/m2, with interracial modifier added, but the load wheel was increased with interfacial modifier increasing. When the TETA: demulsifier: interracial modifier =3:1:3, excellent performance was obtained and the experimental results met the International Slurry Surfacing Association (ISSA) standard. The synthesis process of this emulsifier is simple and the performance used in micro-surface was excellent, so this kind of emulsifier could have a better application future.展开更多
Studies have shown that micro-wedge vortex generators(MVG)can effectively control the flow separation of supersonic boundary layer.In order to improve the flight stability of spinning projectile,the original standard ...Studies have shown that micro-wedge vortex generators(MVG)can effectively control the flow separation of supersonic boundary layer.In order to improve the flight stability of spinning projectile,the original standard 155 mm projectile was taken as an example,and the micro-vanes were mounted at the projectile shoulder to investigate the separation control on the aerodynamic characteristics of projectile.Numerical simulations were performed with the use of DES method for the flow fields of projectiles with and without micro-vanes,and the characteristics of the boundary layer structures and aerodynamic data were compared and discussed.Numerical results show that the micro-vanes can be used to inhibit separation of fluid on projectile surface,and improve the flight stability and firing dispersion of projectile.展开更多
Digital micro-thruster arrays can be used for special missions of micro/nano-satellites with the requirements of high precision and small impulse.This paper presents a novel control allocation algorithm for the digita...Digital micro-thruster arrays can be used for special missions of micro/nano-satellites with the requirements of high precision and small impulse.This paper presents a novel control allocation algorithm for the digital micro-thruster array,namely status graph based control allocation(SGBCA)algorithm,which aims at finding the optimal micro thrusters combination scheme to realize the sequential control synthesis for micro/nano-satellite during real-time orbit control tasks.A mathematical model is set up for the control allocation of this multivariate over-actuated system.Through dividing thrusters into disjoint segments by offline calculation and combining segments dynamically online to provide a sequence of the required impulse for the micro/nano-satellite,the time complexity of the control allocation algorithm decreases significantly.All levels of impulse can be generated by the digital micro thruster arrays and the service life of the arrays can be extended using the segment converting strategy proposed in this paper.The simulation indicates that the algorithm can satisfy the requirements of real-time orbit control for micro/nano-satellites.展开更多
A modularized, network, reconfigurable architecture and design method of embedded control module is proposed. This control module uses a TMS320F2812 chip as the core, and intro- duces modularization, network, reconfig...A modularized, network, reconfigurable architecture and design method of embedded control module is proposed. This control module uses a TMS320F2812 chip as the core, and intro- duces modularization, network, reconfigurable theory to the design of control module to better meet the flexible and reconfigurable control need of assembly line. The design method of the control module is verified by constructing a control experiment based on controlling of precision x - y displace- ment platform through a CAN bus. Experimental results show that the controlling repeat position accuracy of precision x - y platform by control module is 0. 5 μm and the position error is less than 1μm which meet the needs of micro-adjustment pose of assembly line.展开更多
The problem of flapping motion control of Micro Air Vehicles (MAVs) with flapping wings was studied in this paper.Based upon the knowledge of skeletal and muscular components of hummingbird, a dynamic model for flappi...The problem of flapping motion control of Micro Air Vehicles (MAVs) with flapping wings was studied in this paper.Based upon the knowledge of skeletal and muscular components of hummingbird, a dynamic model for flapping wing wasdeveloped.A control scheme inspired by human memory and learning concept was constructed for wing motion control ofMAVs.The salient feature of the proposed control lies in its capabilities to improve the control performance by learning fromexperience and observation on its current and past behaviors, without the need for system dynamic information.Furthermore,the overall control scheme has a fairly simple structure and demands little online computations, making it attractive for real-timeimplementation on MAVs.Both theoretical analysis and computer simulation confirms its effectiveness.展开更多
The proposed phantom is designed for the quality control of micro-SPECT/CT and micro-PET/CT systems. However, it is an assembly of six patterns stored in a cylindrical box enabling to control both micro-SPECT unit in ...The proposed phantom is designed for the quality control of micro-SPECT/CT and micro-PET/CT systems. However, it is an assembly of six patterns stored in a cylindrical box enabling to control both micro-SPECT unit in terms of uniformity, spatial linearity and spatial resolution and micro-CT unit in terms of uniformity, spatial linearity, spatial resolution, diffusion rate, low contrast detectability, Hounsfield unit linearity and slice thickness. The construction material is Plexiglas. As for the implementation, it was made on a micro-SPECT/CT machine of the type “speCZT eXplore CT 120”. Compared to the NEMA NU 4-2008 image quality phantom, this phantom offers micro-CT quality control and is more efficient in control of spatial resolution for micro-SPECT and micro- PET systems.展开更多
This paper presents design, analysis and simulation performance of an active power controller for stable and reliable operation of a micro-grid system. Power balance between generation and consumer is a critical issue...This paper presents design, analysis and simulation performance of an active power controller for stable and reliable operation of a micro-grid system. Power balance between generation and consumer is a critical issue for stable and reliable operation of the micro-grid systems. This issue becomes more critical when a micro-grid system contains stochastic nature distributed generations such as wind and solar because their output power changes non-uniformly. In order to achieve accurate and fast power balance in such a micro-grid system, power in the system has to be regulated continuously. Such an objective can be achieved using droop based alternating current control technique. Because the droop characteristic employed into the developed controller initiates determining the power deviation in the system which is continuously regulated by controlling the current flow into dump power resistors. The designed controller is simulated for the operation of a micro-grid system in stand-alone mode under various operating conditions. The simulated results show the ability of the developed controller for stable and reliable operation of the micro-grid that contains renewable sources. The experimental development of the micro-grid system and the testing of the developed active power controller are presented in PART II of this paper.展开更多
Micro-grid smooth switchover between different operation modes is important for steady operation and reliable power supply of micro-grid. In order to reduce the transient fluctuation of voltage and frequency during sw...Micro-grid smooth switchover between different operation modes is important for steady operation and reliable power supply of micro-grid. In order to reduce the transient fluctuation of voltage and frequency during switchover, this paper proposed a new switchover method based on controller state following. When transferring to island mode, the control method for inverter of storage device changed from PQ control to V/f control. Before switchover, the output of V/f controller is always following the output of PQ controller. So that the sudden change of output is avoided at the moment of switchover. A micro-grid model with photovoltaic and battery is built on DIgSILENT Power Factory simulation software, to simulate micro-grid switchover from grid-connected mode to island mode. Results show this method can effectively suppress the transient fluctuation of voltage and frequency, and reduce the influence of transient process on power grid. This conclusion has important practical significance on micro-grid smooth switchover from grid-con- nected mode to island mode.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
文摘Sensor plays an important role in robotics. Sensors are used to determine the current state of the system. Robotic applications demand sensors with high degrees of repeatability, precision, and reliability. Flex sensor is such a device, which accomplish the above task with great degree of accuracy. The pick and place operation of the robotics arm can be efficiently controlled using micro controller programming. This designed work is an educational based concept as robotic control is an exciting and high challenge research work in recent year.
文摘This paper discusses the design and implementation of single phase PWM inverter using 8051 microcontrol-ler. The main features of 8051 based PWM inverter are simpler design, low cost, maximum range of voltage control and compact in size. The designed PWM inverter is tested on various AC loads like AC motor and intensity control of incandescent lamp in a closed loop environment.
基金The authors thank D.Berger,D.Hofmann and C.Kupka in IFW Dresden for helpful technical support.H.R.acknowledges funding from the DFG(Deutsche Forschungsgemeinschaft)within grant number RE3973/1-1.Q.J.,H.R.and K.N.conceived the work.With the support from N.Y.and X.J.,Q.J.and T.G.fabricated the thermoelectric films and conducted the structural and compositional characterizations.Q.J.prepared microchips and fabricated the on-chip micro temperature controllers.Q.J.and N.P.carried out the temperature-dependent material and device performance measurements.Q.J.and H.R.performed the simulation and analytical calculations.Q.J.,H.R.and K.N.wrote the manuscript with input from the other coauthors.All the authors discussed the results and commented on the manuscript.
文摘Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.
基金Project supported by the Second Stage of Brain Korea 21 Projects,Korea
文摘A 32 kbit OTP(one-time programmable)memory for MCUs(micro-controller units)used in remote controllers was designed.This OTP memory is used for program and data storage.It is required to apply 5.5V to BL(bit-line)and 11V to WL(word-line)for a OTP cell of 0.35μm ETOX(EEPROM tunnel oxide)type by MagnaChip.We use 5V transistors on column data paths to reduce the area of column data paths since they require small areas.In addition,we secure device reliability by using HV(high-voltage)transistors in the WL driver.Furthermore,we change from a static logic to a dynamic logic used for the WL driver in the core circuit.Also,we optimize the WD(write data)switch circuit.Thus,we can implement them with a small-area design.In addition,we implement the address predecoder with a small-area logic circuit.The area of the designed 32 kbit OTP with 5V and HV devices is 674.725μm×258.75μm(=0.1745mm2)and is 56.3% smaller than that using 3.3V devices.
文摘Some disperse dyes were microencapsulated by means of in- situ polymerization. These microencapsulated disperse dyes was extracted respectively by ethanol under certain conditions. The controlled-release properties of disperse dyes through the shell of microcapsules were measured by spectrophotometer. According to the results, it was drawn that the type of disperse dyes, the auxiliaries contained in disperse dyes, the quantity of system controlling medium used and the core/shell ratio of microcapsules play important roles in controlling the release properties of microcapsules. The different controlled- release properties of microcapsules, which were prepared under given conditions, however, would in turn influence the performance of microcapsules in multiple-transfer printing.
基金Research Grants Council of the Hong Kong Special Administrative Region,China Under Grant No.PolyU 5252/07EThe Hong Kong Polytechnic University through the Development of Niche Areas Programme Under Grant No.1-BB95Zhejiang Provincial Natural Science Foundation of China Under Grant No.Y607087)
文摘Magneto-rheological elastomers (MILEs) are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoelastic material is characterized by a complex modulus dependent on vibration frequency and controllable by external magnetic fields. Frequency-domain solution methods for stochastic micro-vibration response analysis of the MRE-based structural systems are developed to derive the system frequency-response function matrices and the expressions of the velocity response spectrum. With these equations, the root-mean-square (RMS) velocity responses in terms of the one-third octave frequency band spectrum can be calculated. Further, the optimization problem of the complex moduli of the MRE cores is defined by minimizing the velocity response spectra and the RMS velocity responses through altering the applied magnetic fields. Simulation results illustrate the influences of MRE parameters on the RMS velocity responses and the high response reduction capacities of the MRE-based structures. In addition, the developed frequency-domain analysis methods are applicable to sandwich beam structures with arbitrary cores characterized by complex shear moduli under stochastic excitations described by power spectral density functions, and are valid for a wide frequency range.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11172326 and 11502280)
文摘The effects of the micro-ramps on supersonic turbulent flow over a forward-facing step(FFS) was experimentally investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering(NPLS)and particle image velocimetry(PIV) techniques. High spatiotemporal resolution images and velocity fields of supersonic flow over the testing model were captured. The fine structures and their spatial evolutionary characteristics without and with the micro-ramps were revealed and compared. The large-scale structures generated by the micro-ramps can survive the downstream FFS flowfield. The micro-ramps control on the flow separation and the separation shock unsteadiness was investigated by PIV results. With the micro-ramps, the reduction in the range of the reversal flow zone in streamwise direction is 50% and the turbulence intensity is also reduced. Moreover, the reduction in the average separated region and in separation shock unsteadiness are 47% and 26%, respectively. The results indicate that the micro-ramps are effective in reducing the flow separation and the separation shock unsteadiness.
文摘The continuous cooling transformation of hot deformation austenite austenite of test steel and the effect of different processing schedules of controlled rolling and controlled cooling on the strength and ductility have been studied. The theory and the experiment base are presented for controlled rolling and controlled cooling of the SBL micro alloyed engineering steel.
文摘Microgrids have been proposed in order to improve reliability and stability of electrical system and to ensure power quality of grid. Microgrid consists of low voltage distribution systems with distributed energy resources, such as wind turbine and photovoltaic power systems, together with storage devices. It is essential to protect a micro grid in both the grid-connected and the islanded mode of operation against all different types of faults. This paper describes micro grid protection and safety concept with central control and monitoring unit where multifunctional intelligent digital relay could be used. This central control & monitoring infrastructure is used for adaptive relay settings strategy for micro grid protection. Also operational safety design concept and fault mitigation technique is proposed to ensure confidence in protection system.
基金supported by the National Science Foundation of China under Grant No.51205046
文摘This paper presents the design and implementation of an energy management system (EMS) with wavelet transform and fuzzy control for a residential micro-grid. The hybrid system in this paper consists of a wind turbine generator, photovoltaic (PV) panels, an electric vehicle (EV), and a super capacitor (SC), which is able to connect or disconnect to the main grid. The control strategy is responsible for compensating the difference between the generated power by the wind and solar generators and the demanded power by the loads. Wavelet transform decomposes the power difference into a smoothed component and a fast fluctuated component. The command approach used for fuzzy logic rules considers the state of charging (SOC) of EV, renewable production, and the load demand as parameters. Furthermore, the command rules are developed in order to ensure a reliable grid when taking into account the EV battery protection to decide the output power of the EV. The model of the hybrid system is developed in detail under Matlab/Simulink software environment.
基金Funded by the National Key Basic Research and Development Plan(No.2012CB724601)the Jiangsu Provincial Natural Science Foundation(No.BK 2008503)
文摘The phenolic emulsifiers used in emulsified asphalt of micro-surfacing, which was the most important tools in the road maintenance, were investigated by control technology. Many factors influencing this reaction were studied and three kinds of phenolic emulsifiers were prepared without catalyst in ethanol. The performance was researched that 2-({2-[2-(2-Amino-ethylamino)-ethylamino]-ethyl-amino}-methyl)-4- nonyl-phenol (abbreviated as TETA) could be used in micro-surface. With addition of 0.5 % demulsifier, the mixing time was extended to 120 seconds obviously, and the cohesion torque (60 min) was 2.8 N*m, which satisfied the opening traffic time shorter than 1 h. The wet track abrasion (6 d) was lower than 807 g/m2, with interracial modifier added, but the load wheel was increased with interfacial modifier increasing. When the TETA: demulsifier: interracial modifier =3:1:3, excellent performance was obtained and the experimental results met the International Slurry Surfacing Association (ISSA) standard. The synthesis process of this emulsifier is simple and the performance used in micro-surface was excellent, so this kind of emulsifier could have a better application future.
文摘Studies have shown that micro-wedge vortex generators(MVG)can effectively control the flow separation of supersonic boundary layer.In order to improve the flight stability of spinning projectile,the original standard 155 mm projectile was taken as an example,and the micro-vanes were mounted at the projectile shoulder to investigate the separation control on the aerodynamic characteristics of projectile.Numerical simulations were performed with the use of DES method for the flow fields of projectiles with and without micro-vanes,and the characteristics of the boundary layer structures and aerodynamic data were compared and discussed.Numerical results show that the micro-vanes can be used to inhibit separation of fluid on projectile surface,and improve the flight stability and firing dispersion of projectile.
文摘Digital micro-thruster arrays can be used for special missions of micro/nano-satellites with the requirements of high precision and small impulse.This paper presents a novel control allocation algorithm for the digital micro-thruster array,namely status graph based control allocation(SGBCA)algorithm,which aims at finding the optimal micro thrusters combination scheme to realize the sequential control synthesis for micro/nano-satellite during real-time orbit control tasks.A mathematical model is set up for the control allocation of this multivariate over-actuated system.Through dividing thrusters into disjoint segments by offline calculation and combining segments dynamically online to provide a sequence of the required impulse for the micro/nano-satellite,the time complexity of the control allocation algorithm decreases significantly.All levels of impulse can be generated by the digital micro thruster arrays and the service life of the arrays can be extended using the segment converting strategy proposed in this paper.The simulation indicates that the algorithm can satisfy the requirements of real-time orbit control for micro/nano-satellites.
基金Supported by National Defense Basic Scientific Research Project(A092000000)High Quality CNC Machine Tool and Basic Manufacturing Equipment Scientific Major Project(2012ZX04010-061)
文摘A modularized, network, reconfigurable architecture and design method of embedded control module is proposed. This control module uses a TMS320F2812 chip as the core, and intro- duces modularization, network, reconfigurable theory to the design of control module to better meet the flexible and reconfigurable control need of assembly line. The design method of the control module is verified by constructing a control experiment based on controlling of precision x - y displace- ment platform through a CAN bus. Experimental results show that the controlling repeat position accuracy of precision x - y platform by control module is 0. 5 μm and the position error is less than 1μm which meet the needs of micro-adjustment pose of assembly line.
文摘The problem of flapping motion control of Micro Air Vehicles (MAVs) with flapping wings was studied in this paper.Based upon the knowledge of skeletal and muscular components of hummingbird, a dynamic model for flapping wing wasdeveloped.A control scheme inspired by human memory and learning concept was constructed for wing motion control ofMAVs.The salient feature of the proposed control lies in its capabilities to improve the control performance by learning fromexperience and observation on its current and past behaviors, without the need for system dynamic information.Furthermore,the overall control scheme has a fairly simple structure and demands little online computations, making it attractive for real-timeimplementation on MAVs.Both theoretical analysis and computer simulation confirms its effectiveness.
文摘The proposed phantom is designed for the quality control of micro-SPECT/CT and micro-PET/CT systems. However, it is an assembly of six patterns stored in a cylindrical box enabling to control both micro-SPECT unit in terms of uniformity, spatial linearity and spatial resolution and micro-CT unit in terms of uniformity, spatial linearity, spatial resolution, diffusion rate, low contrast detectability, Hounsfield unit linearity and slice thickness. The construction material is Plexiglas. As for the implementation, it was made on a micro-SPECT/CT machine of the type “speCZT eXplore CT 120”. Compared to the NEMA NU 4-2008 image quality phantom, this phantom offers micro-CT quality control and is more efficient in control of spatial resolution for micro-SPECT and micro- PET systems.
文摘This paper presents design, analysis and simulation performance of an active power controller for stable and reliable operation of a micro-grid system. Power balance between generation and consumer is a critical issue for stable and reliable operation of the micro-grid systems. This issue becomes more critical when a micro-grid system contains stochastic nature distributed generations such as wind and solar because their output power changes non-uniformly. In order to achieve accurate and fast power balance in such a micro-grid system, power in the system has to be regulated continuously. Such an objective can be achieved using droop based alternating current control technique. Because the droop characteristic employed into the developed controller initiates determining the power deviation in the system which is continuously regulated by controlling the current flow into dump power resistors. The designed controller is simulated for the operation of a micro-grid system in stand-alone mode under various operating conditions. The simulated results show the ability of the developed controller for stable and reliable operation of the micro-grid that contains renewable sources. The experimental development of the micro-grid system and the testing of the developed active power controller are presented in PART II of this paper.
文摘Micro-grid smooth switchover between different operation modes is important for steady operation and reliable power supply of micro-grid. In order to reduce the transient fluctuation of voltage and frequency during switchover, this paper proposed a new switchover method based on controller state following. When transferring to island mode, the control method for inverter of storage device changed from PQ control to V/f control. Before switchover, the output of V/f controller is always following the output of PQ controller. So that the sudden change of output is avoided at the moment of switchover. A micro-grid model with photovoltaic and battery is built on DIgSILENT Power Factory simulation software, to simulate micro-grid switchover from grid-connected mode to island mode. Results show this method can effectively suppress the transient fluctuation of voltage and frequency, and reduce the influence of transient process on power grid. This conclusion has important practical significance on micro-grid smooth switchover from grid-con- nected mode to island mode.
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.