The electro-hydraulic clutch control system controls the transferred torque of gear-shifting clutches in clutch-to-clutch transmissions. A nonlinear dynamic model of an electro-hydraulic clutch shift control system is...The electro-hydraulic clutch control system controls the transferred torque of gear-shifting clutches in clutch-to-clutch transmissions. A nonlinear dynamic model of an electro-hydraulic clutch shift control system is presented. The mechanical and fluid subsystems of all valves are investigated, including their interactions. Model validation of the electro-hydraulic valve system is performed by comparing the simulated and measured pressure curves. The dynamic characteristics of the electro-hydraulic clutch shift control system with different supply pressures and different fluid temperatures are simulated and evaluated. It is found that pipes which are often ignored between the electro-hydraulic valve system and the clutch piston,have strong influence on clutch piston chamber pressures. In order to satisfy the required time and reduce the fluctuation of the clutch piston chamber pressures,the orifices' diameters and valve structure are optimized.展开更多
This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems...This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.展开更多
Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult ch...Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult challenge because gear shifting may cause discomfort to the occupants.To improve the swiftness of gear shifting,this paper proposes a coordinated shift control method based on the dynamic tooth alignment(DTA)algorithm for nonsynchronizer automated mechanical transmissions(NSAMTs)of EVs.After the speed difference between the sleeve(SL)and target dog gear is reduced to a certain value by speed synchronization,angle synchronization is adopted to synchronize the SL quickly to the target tooth slofs angular position predicted by the DTA.A two-speed planetary NS AMT is taken as an example to carry out comparative simulations and bench experiments.Results show that gear shifting duration and maximum jerk are reduced under the shift control with the proposed method,which proves the effectiveness of the proposed coordinated shift control method with DTA.展开更多
In order to improve the driving dynamics and riding comfort of pure electric vehicles,taking a two-speed I-AMT(Inverse-Automatic Mechanical Transmission)with rear friction clutch as the research object,a gear shift st...In order to improve the driving dynamics and riding comfort of pure electric vehicles,taking a two-speed I-AMT(Inverse-Automatic Mechanical Transmission)with rear friction clutch as the research object,a gear shift strategy,which consists of the open-loop control of the clutch position control and the closed-loop control of the drive motor speed control,is proposed.Considering the inherent time-delay and external disturbances within the motor speed adjustment system,a two DOF(degree-of-freedom)Smith predictor with feedforward input is designed to track the target speed of the drive motor.The feedforward input is used to eliminate the influence of clutch sliding friction on the motor speed control,while the feedback speed tracking controller is applied to realize the speed tracking performance with the existence of time-delay and the external disturbance.In order to verify the effectiveness of the gear shift control strategy and the accuracy of the two DOF Smith controller with feedforward control,simulation results comparison is firstly carried out to illustrate the effectiveness of the control scheme.Then,a light pure electric vehicle equipped with I-AMT was used for downshift experiments under large throttle,which is the most difficult working scenario to control the transmission.The experimental results show that the two DOF Smith controller can eliminate the influence of time-delay on the closed-loop control,and the proposed whole gear shift control strategy can limit the clutch slippage time within 1.5 s,resulting in a smaller shift jerk,thus guarantee the driving dynamics and riding comfort simultaneously.展开更多
Considering a quantum model consisting of two effective two-level atoms and a single-mode cavity, this paper investigates the entanglement dynamics between the two atoms, and studies the effect of the Stark shift on t...Considering a quantum model consisting of two effective two-level atoms and a single-mode cavity, this paper investigates the entanglement dynamics between the two atoms, and studies the effect of the Stark shift on the entanglement. The results show that, on the one hand the atom-atom entanglement evolves periodically with time and the periods are affected by the Stark shift; on the other hand, the two atoms are not disentangled at any time when the Stark shift is considered, and for large values of the Stark shift parameter, the two atoms can remain in a stationary entangled state. In addition, for the initially partially entangled atomic state, the atom-atom entanglement can be greatly enhanced due to the presence of Stark shift. These properties show that the Stark shift can be used to control entanglement between two atoms.展开更多
In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrang...In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrange method. And a powertrain model is built in the Matlab/Simulink and veri- fied by the measurements. Considering the shift jerk and friction loss during the shift process, the tracking trajectories of the turbine speed and output shaft speed are defined. Furthermore, the linear quadratic optimal tracking control performance index is proposed. Based on the Pontryagin＇ s mini- mum principle, the optimal control law of the shift process is presented. Finally, the simulation study of the 1 - 2 upshift process under different load conditions is carried out with the powertrain model. The simulation results demonstrate that the shift jerk and friction loss can be significantly re- duced by applying the proposed optimal tracking control method.展开更多
A gearbox in-the-loop control platform using dSPACE real-time system is designed for the study on the control technology of pneumatic selecting and shifting actuators based on rapid control prototyping.The operational...A gearbox in-the-loop control platform using dSPACE real-time system is designed for the study on the control technology of pneumatic selecting and shifting actuators based on rapid control prototyping.The operational principle of such actuators was analyzed using dSPACE hardware and software,resulting in a better knowledge of the logical relationship among solenoid valves,gear positions of cylinders and system input/output.Based on these,a control model was developed under the Matlab/Simulink environment and rapidly improved to meet requirements through experiments.Relevant tests have shown that analysis efficiency on selecting and shifting actuators could be raised and development of control strategy facilitated.展开更多
Taking a heavy-duty truck as a research platform,the changing characteristics of shifting force,shift time,and slipping work are obtained through theoretical analysis and manual shift test of a real vehicle. Based on ...Taking a heavy-duty truck as a research platform,the changing characteristics of shifting force,shift time,and slipping work are obtained through theoretical analysis and manual shift test of a real vehicle. Based on the analysis of the test results,a gear-shifting control strategy of the hydraulic automated shift control system is designed and experimentally verified on the bench. By optimizing the control parameters of high-speed switching valves,a control strategy and parameters are obtained,which can meet the requirements of dynamic performance and reliability.展开更多
This paper presents a very simple scheme for generating quantum controlled phase-shift gate with only one step by using the two vibrational modes of a trapped ion as the two qubits. The scheme couples two vibration de...This paper presents a very simple scheme for generating quantum controlled phase-shift gate with only one step by using the two vibrational modes of a trapped ion as the two qubits. The scheme couples two vibration degrees of freedom coupled with a suitable chosen laser excitation via the ionic states.展开更多
We study the controlling of the Goos-Hanchen （GH） shifts in reflected and transmitted light beams in the triple coupled InGaAs/GaAs quantum dot （QD） nanostructures with electron tunneling and incoherent pumping fi...We study the controlling of the Goos-Hanchen （GH） shifts in reflected and transmitted light beams in the triple coupled InGaAs/GaAs quantum dot （QD） nanostructures with electron tunneling and incoherent pumping field. It is shown that the lateral shift can become either large negative or large positive, which can be controlled by the electron tunneling and the rate of incoherent pump field in different incident angles. It is also demonstrated that the properties of the OH shifts are strongly dependent on the probe absorption beam of the intracavity medium due to the switching from superluminal light propagation to subluminal behavior or vice versa. Our suggested system can be considered as a new theoretical method for developing a new nano-optoelectronic sensor.展开更多
EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a v...EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a vacuum vessel to produce a magnetic field that realizes plasma stabilization. To meet the requirements of a large current and fast response, the multi- ple structure of the carrier phase-shift three-level inverter is presented, which realizes parallelled multi-inverters, raises the equivalent switching frequency of the inverters and improves the per- formance of output waves. In this work the design scheme is analyzed, and the output harmonic characteristic of parallel inverters is studied. The simulation and experimental results confirm that the scheme and control strategy is valid. The power supply system can supply a large current, and has a perfect performance on harmonic features as well as the ability of a fast response.展开更多
This paper deals with the problem of iterative learning control for a class of linear continuous-time switched systems in the presence of a fixed initial shift. Here, the considered switched systems are operated durin...This paper deals with the problem of iterative learning control for a class of linear continuous-time switched systems in the presence of a fixed initial shift. Here, the considered switched systems are operated during a finite time interval repetitively. According to the characteristics of the systems, a PD-type learning scheme is proposed for such switched systems with arbitrary switching rules, and the corresponding output limiting trajectories under the action of the PD-type learning scheme are given. Based on the contraction mapping method, it is shown that this scheme can guarantee the outputs of the systems converge uniformly to the output limiting trajectories of the systems over the whole time interval. Furthermore, the initial rectifying strategies are applied to the systems for eliminating the effect of the fixed initial shift. When the learning scheme is applied to the systems, the outputs of the systems can converge to the desired reference trajectories over a pre-specified interval. Finally, simulation examples illustrate the effectiveness of the proposed method.展开更多
The shift scheduling system of the transmission has an important effect on the dynamic and economic performance of hybrid vehicles. In this work, shift scheduling strategies are developed for parallel hybrid construct...The shift scheduling system of the transmission has an important effect on the dynamic and economic performance of hybrid vehicles. In this work, shift scheduling strategies are developed for parallel hybrid construction vehicles. The effect of power distribution and direction on shift characteristics of the parallel hybrid vehicle with operating loads is evaluated, which must be considered for optimal shift control. A power distribution factor is defined to accurately describe the power distribution and direction in various parallel hybrid systems. This paper proposes a Levenberg-Marquardt algorithm optimized neural network shift scheduling strategy. The methodology contains two objective functions, it is a dynamic combination of a dynamic shift schedule for optimal vehicle acceleration, and an energy-efficient shift schedule for optimal powertrain efficiency. The study is performed on a test bench under typical operating conditions of a wheel loader. The experimental results show that the proposed strategies offer effective and competitive shift performance.展开更多
When the fundamental frequency is shifting, it is hard for traditional repetitive controller to work at the resonant frequencies. In this paper, a novel adaptive repetitive controller for power factor correction syste...When the fundamental frequency is shifting, it is hard for traditional repetitive controller to work at the resonant frequencies. In this paper, a novel adaptive repetitive controller for power factor correction systems is proposed to suppress the current harmonics. Through the controller, the shifting sampling times of the repetitive controller in a fundamental period can be obtained. Mathematical analysis, simulations and physical experiments have validated the effectiveness of the adaptive repetitive controller.展开更多
In this paper, on the basis of the phase shifted controlled zero voltage switch (ZVS) full bridge converter with pulse width modulation (PWM), a novel zero voltage and zero current switch (ZVZCS) PWM converter u...In this paper, on the basis of the phase shifted controlled zero voltage switch (ZVS) full bridge converter with pulse width modulation (PWM), a novel zero voltage and zero current switch (ZVZCS) PWM converter using a simple auxiliary circuit was designed. The ZVZCS soft switch is achieved by the resonance among the resisting electromagnetic deflection capacitor, the capacitor of the simple auxiliary network and the leakage inductor of transformer. There are no dissipation devices of the saturation inductor and the auxiliary switch in the converter, meantime the capacitor of the auxiliary circuit is also used to clamp the voltage of the rectifier, and there is no additional clamped circuit. There is no big circulating current in the converter, all the active and passive devices work on the condition of the low current and voltage stress, and the proposed converter has wide load range and small duty loss.展开更多
Accidental or frequent shift often occurs when the shifting rule is built based on traditional two parameters （i.e., velocity and throttle）, because the speed of engine varies slower than change of throttle opening....Accidental or frequent shift often occurs when the shifting rule is built based on traditional two parameters （i.e., velocity and throttle）, because the speed of engine varies slower than change of throttle opening. Currently, modifying shift point velocity value or throttle by throttle change rate is one of common methods, but the results are not so satisfactory in some working condition such as uphill. The reason is that these methods merely consider throttle change rate which is not enough for a car driving in driver-vehicle-road environment system. So a novel fuzzy control modification strategy is proposed to avoid or reduce those abnormal shift actions. It can adjust shifting rule by the change rate of throttle, current gear position and road environment information, while different gear position and driving environment get corresponding modification value. In order to compare the results of shifting actions, fuel consumption and braking distance, emergent braking in level road and extra-urban driving cycle（EUDC） working conditions with fuzzy shifting schedule modification strategy are simulated digitally. Furthermore, a hardware-in-the-loop simulation platform is introduced to verify its effect in slope road condition according to the ON/OFF numbers of solenoid valve in hydraulic system. The simulation results show that the problem of unexpected shift in those working conditions may be resolved by fuzzy modification strategy. At last, it is concluded that although there is some slight decline in power performance in uphill situation, this fuzzy modification strategy could correctly identify slope of road, decrease braking distance, improve vehicle comfort and fuel economy effectively and prolong the life of clutch system. So, this fuzzy logic shifting strategy provides important references for vehicle intelligent shifting schedule.展开更多
Advent of High Resolution Satellite Data (HRSD) with development of high spatial resolution sensors have revolutionized the generation of large scale maps. Generation of large scale digital utility maps using HRSD inv...Advent of High Resolution Satellite Data (HRSD) with development of high spatial resolution sensors have revolutionized the generation of large scale maps. Generation of large scale digital utility maps using HRSD involves different methodologies and includes several steps wherein errors or spatial shift may be induced at any stage of data generation. It may be interesting to note that the characteristics of the spatial shift vary with methodologies adopted in its processing and has unique implications with respect to the data usage along with its application. Spatial shifts of points on a satellite data is result of unexpected translation and rotation of pixel with respect to the original location. Present study analyzes the spatial shift generated in satellite data with reference to the change in area and orientation of a group of pixels i.e. conformal and equal area properties of the rectified satellite data. This study aims to establish a relationship between the spatial resolutions of the satellite image used for digital map generation with the spatial accuracy achieved. In this study, Ground Control Points (GCP’s) identified on satellite data for a sample study area were validated using Differential Global Positioning System. Five different high resolution satellite images were analyzed to verify changes in area and shape with reference to the GCP’s. The results indicate that with improvement in the spatial resolution, higher precision in the digital maps is accomplished in terms of spatial shift of the points.展开更多
基金National Natural Science Foundation of China(No.51405010)National Science and Technology Support Program,China(No.2011BAG09B00)
文摘The electro-hydraulic clutch control system controls the transferred torque of gear-shifting clutches in clutch-to-clutch transmissions. A nonlinear dynamic model of an electro-hydraulic clutch shift control system is presented. The mechanical and fluid subsystems of all valves are investigated, including their interactions. Model validation of the electro-hydraulic valve system is performed by comparing the simulated and measured pressure curves. The dynamic characteristics of the electro-hydraulic clutch shift control system with different supply pressures and different fluid temperatures are simulated and evaluated. It is found that pipes which are often ignored between the electro-hydraulic valve system and the clutch piston,have strong influence on clutch piston chamber pressures. In order to satisfy the required time and reduce the fluctuation of the clutch piston chamber pressures,the orifices' diameters and valve structure are optimized.
文摘This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.
基金This work was supported by the Science and Technology Planning Project of Guangdong Province,China(Grant Nos.2015B010119002 and 2016B010132001).
文摘Multispeed transmissions can enhance the dynamics and economic performance of electric vehicles(EVs),but the coordinated control of the drive motor and gear shift mechanism during gear shifting is still a difficult challenge because gear shifting may cause discomfort to the occupants.To improve the swiftness of gear shifting,this paper proposes a coordinated shift control method based on the dynamic tooth alignment(DTA)algorithm for nonsynchronizer automated mechanical transmissions(NSAMTs)of EVs.After the speed difference between the sleeve(SL)and target dog gear is reduced to a certain value by speed synchronization,angle synchronization is adopted to synchronize the SL quickly to the target tooth slofs angular position predicted by the DTA.A two-speed planetary NS AMT is taken as an example to carry out comparative simulations and bench experiments.Results show that gear shifting duration and maximum jerk are reduced under the shift control with the proposed method,which proves the effectiveness of the proposed coordinated shift control method with DTA.
基金the National Natural Science Foundation of China under Grant 62003244the Perspective Study Funding of Nanchang Automotive Institute of Intelligence and New Energy+1 种基金Tongji University under Grant TPD-TC202110-10,in part by the Jilin Provincial Science&Technology Department under Grant 20200301011RQthe Fundamental Research Funds for the Central Universities under Grant 22120210160.
文摘In order to improve the driving dynamics and riding comfort of pure electric vehicles,taking a two-speed I-AMT(Inverse-Automatic Mechanical Transmission)with rear friction clutch as the research object,a gear shift strategy,which consists of the open-loop control of the clutch position control and the closed-loop control of the drive motor speed control,is proposed.Considering the inherent time-delay and external disturbances within the motor speed adjustment system,a two DOF(degree-of-freedom)Smith predictor with feedforward input is designed to track the target speed of the drive motor.The feedforward input is used to eliminate the influence of clutch sliding friction on the motor speed control,while the feedback speed tracking controller is applied to realize the speed tracking performance with the existence of time-delay and the external disturbance.In order to verify the effectiveness of the gear shift control strategy and the accuracy of the two DOF Smith controller with feedforward control,simulation results comparison is firstly carried out to illustrate the effectiveness of the control scheme.Then,a light pure electric vehicle equipped with I-AMT was used for downshift experiments under large throttle,which is the most difficult working scenario to control the transmission.The experimental results show that the two DOF Smith controller can eliminate the influence of time-delay on the closed-loop control,and the proposed whole gear shift control strategy can limit the clutch slippage time within 1.5 s,resulting in a smaller shift jerk,thus guarantee the driving dynamics and riding comfort simultaneously.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 10905028)the Natural Science Foundation of Hunan Province of China (Grant No. 07JJ3013)+1 种基金the Program for Science and Technology Department of Henan Province of China (Grant No. 102300410050)the Foundation of Hunan Provincial Education Department of China (Grant No. 06A038)
文摘Considering a quantum model consisting of two effective two-level atoms and a single-mode cavity, this paper investigates the entanglement dynamics between the two atoms, and studies the effect of the Stark shift on the entanglement. The results show that, on the one hand the atom-atom entanglement evolves periodically with time and the periods are affected by the Stark shift; on the other hand, the two atoms are not disentangled at any time when the Stark shift is considered, and for large values of the Stark shift parameter, the two atoms can remain in a stationary entangled state. In addition, for the initially partially entangled atomic state, the atom-atom entanglement can be greatly enhanced due to the presence of Stark shift. These properties show that the Stark shift can be used to control entanglement between two atoms.
基金Supported by the National Natural Science Foundation of China(51475043)
文摘In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrange method. And a powertrain model is built in the Matlab/Simulink and veri- fied by the measurements. Considering the shift jerk and friction loss during the shift process, the tracking trajectories of the turbine speed and output shaft speed are defined. Furthermore, the linear quadratic optimal tracking control performance index is proposed. Based on the Pontryagin＇ s mini- mum principle, the optimal control law of the shift process is presented. Finally, the simulation study of the 1 - 2 upshift process under different load conditions is carried out with the powertrain model. The simulation results demonstrate that the shift jerk and friction loss can be significantly re- duced by applying the proposed optimal tracking control method.
文摘A gearbox in-the-loop control platform using dSPACE real-time system is designed for the study on the control technology of pneumatic selecting and shifting actuators based on rapid control prototyping.The operational principle of such actuators was analyzed using dSPACE hardware and software,resulting in a better knowledge of the logical relationship among solenoid valves,gear positions of cylinders and system input/output.Based on these,a control model was developed under the Matlab/Simulink environment and rapidly improved to meet requirements through experiments.Relevant tests have shown that analysis efficiency on selecting and shifting actuators could be raised and development of control strategy facilitated.
基金Supported by the National High Technology Engineering Program(302011)
文摘Taking a heavy-duty truck as a research platform,the changing characteristics of shifting force,shift time,and slipping work are obtained through theoretical analysis and manual shift test of a real vehicle. Based on the analysis of the test results,a gear-shifting control strategy of the hydraulic automated shift control system is designed and experimentally verified on the bench. By optimizing the control parameters of high-speed switching valves,a control strategy and parameters are obtained,which can meet the requirements of dynamic performance and reliability.
基金supported by the National Natural Science Foundation of China (Grant No 10574001)the Program of the Education Department of Anhui Province (2004kj029) of China+1 种基金the Talent Foundation of Anhui University of Chinathe Youth Program of Fuyang Teachers College of China (Grant Nos 2005LQ03 and 2005LQ04)
文摘This paper presents a very simple scheme for generating quantum controlled phase-shift gate with only one step by using the two vibrational modes of a trapped ion as the two qubits. The scheme couples two vibration degrees of freedom coupled with a suitable chosen laser excitation via the ionic states.
文摘We study the controlling of the Goos-Hanchen （GH） shifts in reflected and transmitted light beams in the triple coupled InGaAs/GaAs quantum dot （QD） nanostructures with electron tunneling and incoherent pumping field. It is shown that the lateral shift can become either large negative or large positive, which can be controlled by the electron tunneling and the rate of incoherent pump field in different incident angles. It is also demonstrated that the properties of the OH shifts are strongly dependent on the probe absorption beam of the intracavity medium due to the switching from superluminal light propagation to subluminal behavior or vice versa. Our suggested system can be considered as a new theoretical method for developing a new nano-optoelectronic sensor.
基金supported by Key Project of National Ninth Five-Year Research Program of China[(1998)1303]
文摘EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a vacuum vessel to produce a magnetic field that realizes plasma stabilization. To meet the requirements of a large current and fast response, the multi- ple structure of the carrier phase-shift three-level inverter is presented, which realizes parallelled multi-inverters, raises the equivalent switching frequency of the inverters and improves the per- formance of output waves. In this work the design scheme is analyzed, and the output harmonic characteristic of parallel inverters is studied. The simulation and experimental results confirm that the scheme and control strategy is valid. The power supply system can supply a large current, and has a perfect performance on harmonic features as well as the ability of a fast response.
基金The NSF(11371013)of Chinathe Research Innovation Program(SKCX17 032)for Graduate Students
文摘This paper deals with the problem of iterative learning control for a class of linear continuous-time switched systems in the presence of a fixed initial shift. Here, the considered switched systems are operated during a finite time interval repetitively. According to the characteristics of the systems, a PD-type learning scheme is proposed for such switched systems with arbitrary switching rules, and the corresponding output limiting trajectories under the action of the PD-type learning scheme are given. Based on the contraction mapping method, it is shown that this scheme can guarantee the outputs of the systems converge uniformly to the output limiting trajectories of the systems over the whole time interval. Furthermore, the initial rectifying strategies are applied to the systems for eliminating the effect of the fixed initial shift. When the learning scheme is applied to the systems, the outputs of the systems can converge to the desired reference trajectories over a pre-specified interval. Finally, simulation examples illustrate the effectiveness of the proposed method.
基金Project(51805200)supported by the National Natural Science Foundation of ChinaProject(20170520096JH)supported by the Science and Technology Development Plan of Jilin Province,ChinaProject(2016YFC0802900)supported by the National Key R&D Program of China
文摘The shift scheduling system of the transmission has an important effect on the dynamic and economic performance of hybrid vehicles. In this work, shift scheduling strategies are developed for parallel hybrid construction vehicles. The effect of power distribution and direction on shift characteristics of the parallel hybrid vehicle with operating loads is evaluated, which must be considered for optimal shift control. A power distribution factor is defined to accurately describe the power distribution and direction in various parallel hybrid systems. This paper proposes a Levenberg-Marquardt algorithm optimized neural network shift scheduling strategy. The methodology contains two objective functions, it is a dynamic combination of a dynamic shift schedule for optimal vehicle acceleration, and an energy-efficient shift schedule for optimal powertrain efficiency. The study is performed on a test bench under typical operating conditions of a wheel loader. The experimental results show that the proposed strategies offer effective and competitive shift performance.
基金the National Natural Science Foundation of China(No.61463037)the Technology Project of Education Department of Jiangxi(No.GJJ14531)the Science&Technology Project of Jiangxi(No.2010BGA01000)
文摘When the fundamental frequency is shifting, it is hard for traditional repetitive controller to work at the resonant frequencies. In this paper, a novel adaptive repetitive controller for power factor correction systems is proposed to suppress the current harmonics. Through the controller, the shifting sampling times of the repetitive controller in a fundamental period can be obtained. Mathematical analysis, simulations and physical experiments have validated the effectiveness of the adaptive repetitive controller.
文摘In this paper, on the basis of the phase shifted controlled zero voltage switch (ZVS) full bridge converter with pulse width modulation (PWM), a novel zero voltage and zero current switch (ZVZCS) PWM converter using a simple auxiliary circuit was designed. The ZVZCS soft switch is achieved by the resonance among the resisting electromagnetic deflection capacitor, the capacitor of the simple auxiliary network and the leakage inductor of transformer. There are no dissipation devices of the saturation inductor and the auxiliary switch in the converter, meantime the capacitor of the auxiliary circuit is also used to clamp the voltage of the rectifier, and there is no additional clamped circuit. There is no big circulating current in the converter, all the active and passive devices work on the condition of the low current and voltage stress, and the proposed converter has wide load range and small duty loss.
基金supported by Science and Technology Commission Shanghai Municipality (Grant No. 06dz1102, Grant No. 08dz1150401)
文摘Accidental or frequent shift often occurs when the shifting rule is built based on traditional two parameters （i.e., velocity and throttle）, because the speed of engine varies slower than change of throttle opening. Currently, modifying shift point velocity value or throttle by throttle change rate is one of common methods, but the results are not so satisfactory in some working condition such as uphill. The reason is that these methods merely consider throttle change rate which is not enough for a car driving in driver-vehicle-road environment system. So a novel fuzzy control modification strategy is proposed to avoid or reduce those abnormal shift actions. It can adjust shifting rule by the change rate of throttle, current gear position and road environment information, while different gear position and driving environment get corresponding modification value. In order to compare the results of shifting actions, fuel consumption and braking distance, emergent braking in level road and extra-urban driving cycle（EUDC） working conditions with fuzzy shifting schedule modification strategy are simulated digitally. Furthermore, a hardware-in-the-loop simulation platform is introduced to verify its effect in slope road condition according to the ON/OFF numbers of solenoid valve in hydraulic system. The simulation results show that the problem of unexpected shift in those working conditions may be resolved by fuzzy modification strategy. At last, it is concluded that although there is some slight decline in power performance in uphill situation, this fuzzy modification strategy could correctly identify slope of road, decrease braking distance, improve vehicle comfort and fuel economy effectively and prolong the life of clutch system. So, this fuzzy logic shifting strategy provides important references for vehicle intelligent shifting schedule.
文摘Advent of High Resolution Satellite Data (HRSD) with development of high spatial resolution sensors have revolutionized the generation of large scale maps. Generation of large scale digital utility maps using HRSD involves different methodologies and includes several steps wherein errors or spatial shift may be induced at any stage of data generation. It may be interesting to note that the characteristics of the spatial shift vary with methodologies adopted in its processing and has unique implications with respect to the data usage along with its application. Spatial shifts of points on a satellite data is result of unexpected translation and rotation of pixel with respect to the original location. Present study analyzes the spatial shift generated in satellite data with reference to the change in area and orientation of a group of pixels i.e. conformal and equal area properties of the rectified satellite data. This study aims to establish a relationship between the spatial resolutions of the satellite image used for digital map generation with the spatial accuracy achieved. In this study, Ground Control Points (GCP’s) identified on satellite data for a sample study area were validated using Differential Global Positioning System. Five different high resolution satellite images were analyzed to verify changes in area and shape with reference to the GCP’s. The results indicate that with improvement in the spatial resolution, higher precision in the digital maps is accomplished in terms of spatial shift of the points.
