The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)at...The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.展开更多
The high proportion of uncertain distributed power sources and the access to large-scale random electric vehicle(EV)charging resources further aggravate the voltage fluctuation of the distribution network,and the exis...The high proportion of uncertain distributed power sources and the access to large-scale random electric vehicle(EV)charging resources further aggravate the voltage fluctuation of the distribution network,and the existing research has not deeply explored the EV active-reactive synergistic regulating characteristics,and failed to realize themulti-timescale synergistic control with other regulatingmeans,For this reason,this paper proposes amultilevel linkage coordinated optimization strategy to reduce the voltage deviation of the distribution network.Firstly,a capacitor bank reactive power compensation voltage control model and a distributed photovoltaic(PV)activereactive power regulationmodel are established.Additionally,an external characteristicmodel of EVactive-reactive power regulation is developed considering the four-quadrant operational characteristics of the EVcharger.Amultiobjective optimization model of the distribution network is then constructed considering the time-series coupling constraints of multiple types of voltage regulators.A multi-timescale control strategy is proposed by considering the impact of voltage regulators on active-reactive EV energy consumption and PV energy consumption.Then,a four-stage voltage control optimization strategy is proposed for various types of voltage regulators with multiple time scales.Themulti-objective optimization is solved with the improvedDrosophila algorithmto realize the power fluctuation control of the distribution network and themulti-stage voltage control optimization.Simulation results validate that the proposed voltage control optimization strategy achieves the coordinated control of decentralized voltage control resources in the distribution network.It effectively reduces the voltage deviation of the distribution network while ensuring the energy demand of EV users and enhancing the stability and economic efficiency of the distribution network.展开更多
Electric tractors(ETs)with mounted implements form operating units.There are significant differences in parameters such as shape,firmness,and moisture content of the soil in contact with the tractor and implements whe...Electric tractors(ETs)with mounted implements form operating units.There are significant differences in parameters such as shape,firmness,and moisture content of the soil in contact with the tractor and implements when working in complex terrains such as field stubble,waterlogged silt,and loose/firm terrain.These differentiated dynamics prevent cooperation between ETs and operating implements under independent control,resulting in poor quality operations and low energy efficiency.We propose a control mechanism for ETs and implements to achieve full life cycle management of collaborative control tasks,instantaneous intertask interaction,and a multitask synchronization mechanism.To address the internal redundant communication problems caused by traditional distributed microcontrol units,we break through the underlying technology of unit data processing and interaction and develop an integrated high-performance controller structure with high processing capacity and high-and low-speed communication interfaces.On the basis of hierarchical stepwise control theory,a hierarchical real-time operating system is designed.This system realizes a preemptive kernel response of computational tasks and competitive-collaborative synchronization among tasks;overcomes the low-latency response of collaborative control tasks,instantaneous information interaction,and multitask synchronization problems;and provides system-level support for deep collaborative operation control of units.To demonstrate and validate the proposed collaborative control mechanism,a plowing collaborative operation management strategy is designed and deployed.The experimental results show that the communication delay of collaborative tasks is as low as 83μs,the solution time of complex collaborative equations is as low as 46 ms,the mechanical efficiency of the ET is increased by 9.07%,the efficiency of the drive motor is increased by 9.72%,the stability of the operation speed is increased by 106.25%,and the stability of the plowing depth reaches 94.98%.Our work meets the hardware and software requirements for realizing complex collaborative control of ET units and improves the operational quality and operational energy efficiency in real vehicle demonstrations.展开更多
Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a pro...Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.展开更多
Vehicle collision avoidance(CA)has been widely studied to improve road traffic safety.However,most evasion assistance control methods face challenges in effectively coordinating collision avoidance safety and human-ma...Vehicle collision avoidance(CA)has been widely studied to improve road traffic safety.However,most evasion assistance control methods face challenges in effectively coordinating collision avoidance safety and human-machine interaction conflict.This paper introduces a novel multi-mode evasion assistance control(MEAC)method for intelligent distributed-drive electric vehicles.A reference safety area is established considering the vehicle safety and stability requirements,which serves as a guiding principle for evading obstacles.The proposed method includes two control modes:Shared-EAC(S-EAC)and Emergency-EAC(E-EAC).In S-EAC,an integrated human-machine authority allocation mechanism is designed to mitigate conflicts between human drivers and the control system during collision avoidance.The E-EAC mode is tailored for situations where the driver has no collision avoidance behavior and utilizes model predictive control to generate additional yaw moments for collision avoidance.Simulation and experimental results indicate that the proposed method reduces human-machine conflict and assists the driver in safe collision avoidance in the S-EAC mode under various driver conditions.In addition,it enhances the vehicle responsiveness and reduces the extent of emergency steering in the E-EAC mode while improving the safety and stability during the collision avoidance process.展开更多
The integration of eco-driving and cooperative adaptive cruise control(CACC)with platoon cooperative control(eco-CACC)has emerged as a pivotal approach for improving vehicle energy efficiency.Nonetheless,the prevailin...The integration of eco-driving and cooperative adaptive cruise control(CACC)with platoon cooperative control(eco-CACC)has emerged as a pivotal approach for improving vehicle energy efficiency.Nonetheless,the prevailing eco-CACC implementations still exhibit limitations in fully harnessing the potential energy savings.This can be attributed to the intricate nature of the problem,characterized by its high nonlinearity and non-convexity,making it challenging for conventional solving methods to find solutions.In this paper,a novel strategy based on a decentralized model predictive control(MPC)framework,called predictive ecological cooperative control(PECC),is proposed for vehicle platoon control on hilly roads,aiming to maximize the overall energy efficiency of the platoon.Unlike most existing literature that focuses on suboptimal coordination under predefined leading vehicle trajectories,this strategy employs an approach based on the combination of a long short-term memory network(LSTM)and genetic algorithm(GA)optimization(GA-LSTM)to predict the future speed of the leading vehicle.Notably,a function named the NotchFilter function(NF(?))is introduced to transform the hard state constraints in the eco-CACC problem,thereby alleviating the burden of problem-solving.Finally,through simulation comparisons between PECC and a strategy based on the common eco-CACC modifications,the effectiveness of PECC in improving platoon energy efficiency is demonstrated.展开更多
Dear Editor,This letter presents a new secure hierarchical control strategy for steering tracking of in-wheel motor driven(IWMD)electric vehicle(EV)subject to limited network resources,hybrid cyber-attacks,model nonli...Dear Editor,This letter presents a new secure hierarchical control strategy for steering tracking of in-wheel motor driven(IWMD)electric vehicle(EV)subject to limited network resources,hybrid cyber-attacks,model nonlinearities,actuator redundancy and airflow disturbance.A hierarchical control architecture is proposed specifically for solving the problems of nonlinear system modeling and actuator redundancy.By utilizing the advantages of fully actuated system(FAS)approach,a nonlinear virtual controller against airflow disturbance is constructed in upper layer system and an event-triggered nonlinear distributed controller is proposed in lower layer system under stochastic hybrid cyber-attacks.A case study of overtaking task is carried out to validate the FAS-based hierarchical control strategy.展开更多
In the current social environment,the importance of energy conservation and emission reduction is increasing day by day for both the country and its people.Electronic and electrical products,as important items for peo...In the current social environment,the importance of energy conservation and emission reduction is increasing day by day for both the country and its people.Electronic and electrical products,as important items for people’s production and life,require high attention from industry insiders in terms of their energy efficiency testing.Relying on energy efficiency testing can achieve the goal of energy conservation and emission reduction,and related quality control technologies will also inject new momentum into the green development of the industry.This article will discuss the practical strategies of quality control technology for energy efficiency testing of electronic and electrical products based on the significance of such testing,hoping to provide some help.展开更多
Objective:To evaluate the efficacy and safety of transcutaneous electrical acupoint stimulation(TEAS)for muscle atrophy in patients with immobilization after surgical fixation of foot and ankle fractures.Methods:This ...Objective:To evaluate the efficacy and safety of transcutaneous electrical acupoint stimulation(TEAS)for muscle atrophy in patients with immobilization after surgical fixation of foot and ankle fractures.Methods:This was a two-arm randomized controlled trial wherein 80 patients were recruited and divided into control(n=40)and intervention(n=40)groups.The control group received conventional orthopedic treatment,whereas the intervention group received TEAS and conventional treatment.The intervention group received TEAS 3 times a week for 30 min each time for 8 weeks.The primary out-comes were muscle thickness(MT)and cross-sectional area(CSA)of the rectus femoris and gastroc-nemius muscles,whereas the secondary outcome measure was echo intensity(EI).Data were collected before the fixation operations(baseline assessment)and 4 and 8 weeks after intervention.Results:Compared with baseline,the MT and CSA were reduced in both groups by the end of treatment,whereas EI increased in both groups.At week 4,the reduction in the rectus femoris CSA in the inter-vention group was significantly lower than that in the control group(P=0.02);however,the between-group differences in the MT and EI(all P>0.05)were not significant.No serious adverse events were observed in either group.Conclusion:Our study showed that TEAS can improve muscle atrophy by attenuating the decline in the muscle CSA.Because this was only a pilot trial,subsequent studies will need longer follow-ups and larger sample sizes.展开更多
The piezoelectric actuator has been widely used in precision instruments and precision control. However, hysteresis, nonlinearity and creep exist in the actuator, which limit actuator applications and affect accuracy....The piezoelectric actuator has been widely used in precision instruments and precision control. However, hysteresis, nonlinearity and creep exist in the actuator, which limit actuator applications and affect accuracy. This thesis introduces fuzzy control as the algorithm of a closed-loop control system to control the piezoelectric actuator. Fuzzy control can make this closed-looped system not only have high linearity, repeatability, accuracy and few overshoot, but isalso easily used.展开更多
In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is sing...In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current（DC）bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.展开更多
OBJECTIVE:To investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on enhanced recovery after surgery (ERAS) in laparoscopic colorectal cancer resection and its clinical significance.METHODS:...OBJECTIVE:To investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on enhanced recovery after surgery (ERAS) in laparoscopic colorectal cancer resection and its clinical significance.METHODS:Sixty-four patients undergoing laparoscopic colorectal resection were randomly divided into two groups,the control group (group A) and the TEAS group (group B).Patients in the TEAS group received electroacupuncture stimulation of bilateral Zusanli (ST 36) at 30 min before anesthesia to the end of surgery.The patients in the control group were not given the stimulation.Perioperative anesthesia management of the two groups were performed according to the ERAS guidelines,and postoperative patient-controlled intravenous analgesia (PCIA) was used.The amount of remifentanil used in the two groups was observed and recorded,and the visual analogue scale (VAS) of the 4,12,24 and 48 h after surgery in the two groups was recorded.Moreover,postoperative anal exhaust time,postoperative feeding time,postoperative first ambulation time and postoperative hospital stay length were compared between the two groups.RESULTS:Compared with group A,the VAS score of group B decreased significantly at 48 h after operation (P < 0.05).The postoperative anal exhaust time in group B was significantly shorter than that of group A (P < 0.05).There was no significant difference between the two groups with regards to remifentanil consumption,postoperative feeding time,postoperative first ambulation time and postoperative hospital stay (all P > 0.05).CONCLUSION:TEAS can promote the recovery of postoperative gastrointestinal function and reduce the pain intensity 48 h after surgery,thus satisfying the need of early postoperative analgesia.展开更多
For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And dir...For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And direct yaw-moment control(DYC)has been widely studied and applied to vehicle stability control.Good vehicle handling performance:quick yaw rate transient response,small overshoot,high steady yaw rate gain,etc,is required by drivers under normal conditions,which is less concerned,however.Based on the hierarchical control methodology,a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed.The upper-loop control system consists of two parts:a state feedback controller,which aims to realize the ideal transient response of yaw rate,with a vehicle sideslip angle observer;and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain.Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors,the integrated time and absolute error(ITAE)function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix.Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method:yaw rate rising time is reduced,steady yaw rate gain is increased,vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced.The control system improves vehicle handling performance under normal conditions in both transient and steady response.State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.展开更多
Resolvers are normally employed for rotor positioning in motors for electric vehicles, but resolvers are expensive and vulnerable to vibrations. Hall sensors have the advantages of low cost and high reliability, but t...Resolvers are normally employed for rotor positioning in motors for electric vehicles, but resolvers are expensive and vulnerable to vibrations. Hall sensors have the advantages of low cost and high reliability, but the positioning accuracy is low. Motors with Hall sensors are typically controlled by six-step commutation algorithm, which brings high torque ripple. This paper studies the high-performance driving and braking control of the in-wheel permanent magnetic synchronous motor （PMSM） based on low-resolution Hall sensors. Field oriented control （FOC） based on Hall-effect sensors is developed to reduce the torque ripple. The positioning accuracy of the Hall sensors is improved by interpolation between two consecutive Hall signals using the estimated motor speed. The position error from the misalignment of the Hall sensors is compensated by the precise calibration of Hall transition timing. The braking control algorithms based on six-step commutation and FOC are studied. Two variants of the six-step commutation braking control, namely, half-bridge commutation and full-bridge commutation, are discussed and compared, which shows that the full-bridge commutation could better explore the potential of the back electro-motive forces （EMF）, thus can deliver higher efficiency and smaller current ripple. The FOC braking is analyzed with the phasor diagrams. At a given motor speed, the motor turns from the regenerative braking mode into the plug braking mode if the braking torque exceeds a certain limit, which is proportional to the motor speed. Tests in the dynamometer show that a smooth control could be realized by FOC driving control and the highest efficiency and the smallest current ripple could be achieved by FOC braking control, compared to six-step commutation braking control. Therefore, FOC braking is selected as the braking control algorithm for electric vehicles. The proposed research ensures a good motor control performance while maintaining low cost and high reliability.展开更多
Coasting in gear is a common driving mode for the conventional vehicle equipped with the internal combustion engine（ICE）, and the assistant braking function of ICE is utilized to decelerate the vehicle in this mode....Coasting in gear is a common driving mode for the conventional vehicle equipped with the internal combustion engine（ICE）, and the assistant braking function of ICE is utilized to decelerate the vehicle in this mode. However, the electric vehicle（EV） does not have this feature in the coasting mode due to the relatively small inertia of the driving motor, so it will cause the driver cannot obtain the similar driving feeling to that of the conventional vehicle, and even a traffic accident may occur if the driver cannot immediately adapt to the changes. In this paper, the coasting control for EV is researched based on the driving feeling. A conventional vehicle equipped with continuously variable transmission（CVT） is taken as the reference vehicle, and the combined simulation model of EV is established based on AVL CRUISE and MATLAB/Simulink. The torque characteristic of the CVT output shaft is measured in coasting mode, and the data are smoothed and fitted to a polynomial curve. For the EV in coasting mode, if the state of charge（SOC） of the battery is below 95%, the polynomial curve is used as the control target for the torque characteristic of the driving motor, otherwise, the required torque is replaced by hydraulic braking torque to keep the same deceleration. The co-simulation of Matlab/Simulink/Stateflow and AVL CRUISE, as well as the hardware-in-loop experiment combined with d SPACE are carried out to verify the effectiveness and the real-time performance of the control algorithm. The results show that the EV with coasting braking control system has similar driving feeling to that of the reference vehicle, meanwhile, the battery SOC can be increased by 0.036% and 0.021% in the initial speed of 100 km/h and 50 km/h, respectively. The proposed control algorithm for EV is beneficial to improve the driving feeling in coasting mode, and it also makes the EV has the assistant braking function.展开更多
This paper addresses the co-design problem of decentralized dynamic event-triggered communication and active suspension control for an in-wheel motor driven electric vehicle equipped with a dynamic damper. The main ob...This paper addresses the co-design problem of decentralized dynamic event-triggered communication and active suspension control for an in-wheel motor driven electric vehicle equipped with a dynamic damper. The main objective is to simultaneously improve the desired suspension performance caused by various road disturbances and alleviate the network resource utilization for the concerned in-vehicle networked suspension system. First, a T-S fuzzy active suspension model of an electric vehicle under dynamic damping is established. Second,a novel decentralized dynamic event-triggered communication mechanism is developed to regulate each sensor's data transmissions such that sampled data packets on each sensor are scheduled in an independent manner. In contrast to the traditional static triggering mechanisms, a key feature of the proposed mechanism is that the threshold parameter in the event trigger is adjusted adaptively over time to reduce the network resources occupancy. Third, co-design criteria for the desired event-triggered fuzzy controller and dynamic triggering mechanisms are derived. Finally, comprehensive comparative simulation studies of a 3-degrees-of-freedom quarter suspension model are provided under both bump road disturbance and ISO-2631 classified random road disturbance to validate the effectiveness of the proposed co-design approach. It is shown that ride comfort can be greatly improved in either road disturbance case and the suspension deflection, dynamic tyre load and actuator control input are all kept below the prescribed maximum allowable limits, while simultaneously maintaining desirable communication efficiency.展开更多
The principle of electric braking system is analyzed and an anti-skid braking system based on the slip rate control is proposed.The fuzzy-PID controller with parameter self-adjustment feature is designed for the anti-...The principle of electric braking system is analyzed and an anti-skid braking system based on the slip rate control is proposed.The fuzzy-PID controller with parameter self-adjustment feature is designed for the anti-skid braking system.The dynamic model of aircraft ground braking is established in the simulation environment of MATLAB/SIMULINK,and simulation results of dry runway and wet runway are presented.The results show that the fuzzy-PID controller with parameter self-adjustment feature for the electric anti-skid braking system keeps working in the state of stability and the brake efficiencies are increased to 93%on dry runway and 82%on wet runway respectively.展开更多
In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control ...In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.展开更多
Electrically controlled rotor （ECR） system has the potential to enhance the rotor perfor- mance by applying higher harmonic flap inputs. In order to explore the feasibility and effectiveness for ECR performance enha...Electrically controlled rotor （ECR） system has the potential to enhance the rotor perfor- mance by applying higher harmonic flap inputs. In order to explore the feasibility and effectiveness for ECR performance enhancement using closed-loop control method, firstly, an ECR rotor performance analysis model based on helicopter flight dynamic model is established, which can reflect the performance characteristics of ECR helicopter at high advance ratio. Based on the simulation platform, an active control method named adaptive T-matrix algorithm is adopted to explore the feasibility and effectiveness for ECR performance enhancement. The simulation results verify the effectiveness of this closed-loop control method. For the sample ECR helicopter, about 3% rotor power reduction is obtained with the optimum 2/rev flap inputs at the advance ratio of 0.34. And through analyzing the distributions of attack of angle and drag in rotor disk, the underlying physical essence of ECR power reduction is cleared. Furthermore, the influence of the key control parameters, including convergence factor and weighting matrix, on the effectiveness of closed-loop control for ECR performance enhancement is explored. Some useful results are summarized, which can be used to direct the future active control law design of ECR performance enhancement.展开更多
In parallel hybrid electrical vehicle(PHEV)equipped with automatic mechanical transmission(AMT),the driving smoothness and the clutch abrasion are the primary considerations for powertrain control during gearshift and...In parallel hybrid electrical vehicle(PHEV)equipped with automatic mechanical transmission(AMT),the driving smoothness and the clutch abrasion are the primary considerations for powertrain control during gearshift and clutch operation.To improve these performance indexes of PHEV,a coordinated control system is proposed through the analyzing of HEV powertrain dynamic characteristics.Using the method of minimum principle,the input torque of transmission is optimized to improve the driving smoothness of vehicle.Using the methods of fuzzy logic and fuzzy-PID,the engaging speed of clutch and the throttle opening of engine are manipulated to ensure the smoothness of clutch engagement and reduce the abrasion of clutch friction plates.The motor provides the difference between the required input torque of transmission and the torque transmitted through clutch plates.Results of simulation and experiments show that the proposed control strategy performs better than the contrastive control system,the smoothness of driving and the abrasion of clutch can be improved simultaneously.展开更多
基金supported by the National Natural Science Foundation of China(22265021,52231007,and 12327804)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.
基金funded by the State Grid Corporation Science and Technology Project(5108-202218280A-2-391-XG).
文摘The high proportion of uncertain distributed power sources and the access to large-scale random electric vehicle(EV)charging resources further aggravate the voltage fluctuation of the distribution network,and the existing research has not deeply explored the EV active-reactive synergistic regulating characteristics,and failed to realize themulti-timescale synergistic control with other regulatingmeans,For this reason,this paper proposes amultilevel linkage coordinated optimization strategy to reduce the voltage deviation of the distribution network.Firstly,a capacitor bank reactive power compensation voltage control model and a distributed photovoltaic(PV)activereactive power regulationmodel are established.Additionally,an external characteristicmodel of EVactive-reactive power regulation is developed considering the four-quadrant operational characteristics of the EVcharger.Amultiobjective optimization model of the distribution network is then constructed considering the time-series coupling constraints of multiple types of voltage regulators.A multi-timescale control strategy is proposed by considering the impact of voltage regulators on active-reactive EV energy consumption and PV energy consumption.Then,a four-stage voltage control optimization strategy is proposed for various types of voltage regulators with multiple time scales.Themulti-objective optimization is solved with the improvedDrosophila algorithmto realize the power fluctuation control of the distribution network and themulti-stage voltage control optimization.Simulation results validate that the proposed voltage control optimization strategy achieves the coordinated control of decentralized voltage control resources in the distribution network.It effectively reduces the voltage deviation of the distribution network while ensuring the energy demand of EV users and enhancing the stability and economic efficiency of the distribution network.
基金supported by the National Key Research and Development Plan of China(2022YFD2001202)the National Natural Science Foundation of China(32301719 and 52272444)the 2115 Talent Development Program of China Agricultural University.
文摘Electric tractors(ETs)with mounted implements form operating units.There are significant differences in parameters such as shape,firmness,and moisture content of the soil in contact with the tractor and implements when working in complex terrains such as field stubble,waterlogged silt,and loose/firm terrain.These differentiated dynamics prevent cooperation between ETs and operating implements under independent control,resulting in poor quality operations and low energy efficiency.We propose a control mechanism for ETs and implements to achieve full life cycle management of collaborative control tasks,instantaneous intertask interaction,and a multitask synchronization mechanism.To address the internal redundant communication problems caused by traditional distributed microcontrol units,we break through the underlying technology of unit data processing and interaction and develop an integrated high-performance controller structure with high processing capacity and high-and low-speed communication interfaces.On the basis of hierarchical stepwise control theory,a hierarchical real-time operating system is designed.This system realizes a preemptive kernel response of computational tasks and competitive-collaborative synchronization among tasks;overcomes the low-latency response of collaborative control tasks,instantaneous information interaction,and multitask synchronization problems;and provides system-level support for deep collaborative operation control of units.To demonstrate and validate the proposed collaborative control mechanism,a plowing collaborative operation management strategy is designed and deployed.The experimental results show that the communication delay of collaborative tasks is as low as 83μs,the solution time of complex collaborative equations is as low as 46 ms,the mechanical efficiency of the ET is increased by 9.07%,the efficiency of the drive motor is increased by 9.72%,the stability of the operation speed is increased by 106.25%,and the stability of the plowing depth reaches 94.98%.Our work meets the hardware and software requirements for realizing complex collaborative control of ET units and improves the operational quality and operational energy efficiency in real vehicle demonstrations.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074213,11574108,and 12104253)the National Key R&D Program of China(Grant No.2022YFA1403103)+2 种基金the Major Basic Program of the Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Provincial(Grant No.ZR2023MA082)the Project of Introduction and Cultivation for Young Innovative Talents in Colleges and Universities of Shandong Province。
文摘Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.
基金Supported by National Key Research and Development Program of China(Grant Nos.2022YFE0117100 and 2021YFB250120101)National Natural Science Foundation of China(Grant No.52325212)+1 种基金Shanghai Municipal Automotive Industry Science,Technology Development Foundation(Grant No.2203)the SAIC Motor Corporation Limited(Grant No.2023023).
文摘Vehicle collision avoidance(CA)has been widely studied to improve road traffic safety.However,most evasion assistance control methods face challenges in effectively coordinating collision avoidance safety and human-machine interaction conflict.This paper introduces a novel multi-mode evasion assistance control(MEAC)method for intelligent distributed-drive electric vehicles.A reference safety area is established considering the vehicle safety and stability requirements,which serves as a guiding principle for evading obstacles.The proposed method includes two control modes:Shared-EAC(S-EAC)and Emergency-EAC(E-EAC).In S-EAC,an integrated human-machine authority allocation mechanism is designed to mitigate conflicts between human drivers and the control system during collision avoidance.The E-EAC mode is tailored for situations where the driver has no collision avoidance behavior and utilizes model predictive control to generate additional yaw moments for collision avoidance.Simulation and experimental results indicate that the proposed method reduces human-machine conflict and assists the driver in safe collision avoidance in the S-EAC mode under various driver conditions.In addition,it enhances the vehicle responsiveness and reduces the extent of emergency steering in the E-EAC mode while improving the safety and stability during the collision avoidance process.
基金Supported by National Natural Science Foundation of China(Grant Nos.52172383,51805081)Jiangsu Provincial Postgraduate Research&Practice Innovation Program(Grant No.KYCX22_0196)。
文摘The integration of eco-driving and cooperative adaptive cruise control(CACC)with platoon cooperative control(eco-CACC)has emerged as a pivotal approach for improving vehicle energy efficiency.Nonetheless,the prevailing eco-CACC implementations still exhibit limitations in fully harnessing the potential energy savings.This can be attributed to the intricate nature of the problem,characterized by its high nonlinearity and non-convexity,making it challenging for conventional solving methods to find solutions.In this paper,a novel strategy based on a decentralized model predictive control(MPC)framework,called predictive ecological cooperative control(PECC),is proposed for vehicle platoon control on hilly roads,aiming to maximize the overall energy efficiency of the platoon.Unlike most existing literature that focuses on suboptimal coordination under predefined leading vehicle trajectories,this strategy employs an approach based on the combination of a long short-term memory network(LSTM)and genetic algorithm(GA)optimization(GA-LSTM)to predict the future speed of the leading vehicle.Notably,a function named the NotchFilter function(NF(?))is introduced to transform the hard state constraints in the eco-CACC problem,thereby alleviating the burden of problem-solving.Finally,through simulation comparisons between PECC and a strategy based on the common eco-CACC modifications,the effectiveness of PECC in improving platoon energy efficiency is demonstrated.
基金supported by the National Natural Science Foundation of China(62173209,61773238)the Science Center Program of National Natural Science Foundation of China(62188101).
文摘Dear Editor,This letter presents a new secure hierarchical control strategy for steering tracking of in-wheel motor driven(IWMD)electric vehicle(EV)subject to limited network resources,hybrid cyber-attacks,model nonlinearities,actuator redundancy and airflow disturbance.A hierarchical control architecture is proposed specifically for solving the problems of nonlinear system modeling and actuator redundancy.By utilizing the advantages of fully actuated system(FAS)approach,a nonlinear virtual controller against airflow disturbance is constructed in upper layer system and an event-triggered nonlinear distributed controller is proposed in lower layer system under stochastic hybrid cyber-attacks.A case study of overtaking task is carried out to validate the FAS-based hierarchical control strategy.
文摘In the current social environment,the importance of energy conservation and emission reduction is increasing day by day for both the country and its people.Electronic and electrical products,as important items for people’s production and life,require high attention from industry insiders in terms of their energy efficiency testing.Relying on energy efficiency testing can achieve the goal of energy conservation and emission reduction,and related quality control technologies will also inject new momentum into the green development of the industry.This article will discuss the practical strategies of quality control technology for energy efficiency testing of electronic and electrical products based on the significance of such testing,hoping to provide some help.
基金supported by the funded project(HYZHX M05005)in the field of space medical experiments of manned spaceflight engineering.
文摘Objective:To evaluate the efficacy and safety of transcutaneous electrical acupoint stimulation(TEAS)for muscle atrophy in patients with immobilization after surgical fixation of foot and ankle fractures.Methods:This was a two-arm randomized controlled trial wherein 80 patients were recruited and divided into control(n=40)and intervention(n=40)groups.The control group received conventional orthopedic treatment,whereas the intervention group received TEAS and conventional treatment.The intervention group received TEAS 3 times a week for 30 min each time for 8 weeks.The primary out-comes were muscle thickness(MT)and cross-sectional area(CSA)of the rectus femoris and gastroc-nemius muscles,whereas the secondary outcome measure was echo intensity(EI).Data were collected before the fixation operations(baseline assessment)and 4 and 8 weeks after intervention.Results:Compared with baseline,the MT and CSA were reduced in both groups by the end of treatment,whereas EI increased in both groups.At week 4,the reduction in the rectus femoris CSA in the inter-vention group was significantly lower than that in the control group(P=0.02);however,the between-group differences in the MT and EI(all P>0.05)were not significant.No serious adverse events were observed in either group.Conclusion:Our study showed that TEAS can improve muscle atrophy by attenuating the decline in the muscle CSA.Because this was only a pilot trial,subsequent studies will need longer follow-ups and larger sample sizes.
文摘The piezoelectric actuator has been widely used in precision instruments and precision control. However, hysteresis, nonlinearity and creep exist in the actuator, which limit actuator applications and affect accuracy. This thesis introduces fuzzy control as the algorithm of a closed-loop control system to control the piezoelectric actuator. Fuzzy control can make this closed-looped system not only have high linearity, repeatability, accuracy and few overshoot, but isalso easily used.
基金Natural Science Foundation of Gansu Province(Joint)Project(No.213244)Natural Science Foundation of Gansu Province(No.145RJZA136)Youth Science Foundation of Lanzhou Jiaotong University(No.2013040)
文摘In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current（DC）bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure stability of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accomplished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modulation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal control characteristics in case of sensor failure although part of the system performance is lost,thus the correctness of the proposed method is verified.
文摘OBJECTIVE:To investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on enhanced recovery after surgery (ERAS) in laparoscopic colorectal cancer resection and its clinical significance.METHODS:Sixty-four patients undergoing laparoscopic colorectal resection were randomly divided into two groups,the control group (group A) and the TEAS group (group B).Patients in the TEAS group received electroacupuncture stimulation of bilateral Zusanli (ST 36) at 30 min before anesthesia to the end of surgery.The patients in the control group were not given the stimulation.Perioperative anesthesia management of the two groups were performed according to the ERAS guidelines,and postoperative patient-controlled intravenous analgesia (PCIA) was used.The amount of remifentanil used in the two groups was observed and recorded,and the visual analogue scale (VAS) of the 4,12,24 and 48 h after surgery in the two groups was recorded.Moreover,postoperative anal exhaust time,postoperative feeding time,postoperative first ambulation time and postoperative hospital stay length were compared between the two groups.RESULTS:Compared with group A,the VAS score of group B decreased significantly at 48 h after operation (P < 0.05).The postoperative anal exhaust time in group B was significantly shorter than that of group A (P < 0.05).There was no significant difference between the two groups with regards to remifentanil consumption,postoperative feeding time,postoperative first ambulation time and postoperative hospital stay (all P > 0.05).CONCLUSION:TEAS can promote the recovery of postoperative gastrointestinal function and reduce the pain intensity 48 h after surgery,thus satisfying the need of early postoperative analgesia.
基金Supported by National Basic Research Program of China(973 Program,Grant No.2011CB711200)National Science and Technology Support Program of China(Grant No.2015BAG17B00)National Natural Science Foundation of China(Grant No.51475333)
文摘For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And direct yaw-moment control(DYC)has been widely studied and applied to vehicle stability control.Good vehicle handling performance:quick yaw rate transient response,small overshoot,high steady yaw rate gain,etc,is required by drivers under normal conditions,which is less concerned,however.Based on the hierarchical control methodology,a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed.The upper-loop control system consists of two parts:a state feedback controller,which aims to realize the ideal transient response of yaw rate,with a vehicle sideslip angle observer;and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain.Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors,the integrated time and absolute error(ITAE)function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix.Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method:yaw rate rising time is reduced,steady yaw rate gain is increased,vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced.The control system improves vehicle handling performance under normal conditions in both transient and steady response.State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.
基金supported by National Hi-tech Research and Development Program of China (863 Program,Grant No.2008AA11A126)Program for New Century Excellent Talents in University of China (Grant No. NCET-10-0498)
文摘Resolvers are normally employed for rotor positioning in motors for electric vehicles, but resolvers are expensive and vulnerable to vibrations. Hall sensors have the advantages of low cost and high reliability, but the positioning accuracy is low. Motors with Hall sensors are typically controlled by six-step commutation algorithm, which brings high torque ripple. This paper studies the high-performance driving and braking control of the in-wheel permanent magnetic synchronous motor （PMSM） based on low-resolution Hall sensors. Field oriented control （FOC） based on Hall-effect sensors is developed to reduce the torque ripple. The positioning accuracy of the Hall sensors is improved by interpolation between two consecutive Hall signals using the estimated motor speed. The position error from the misalignment of the Hall sensors is compensated by the precise calibration of Hall transition timing. The braking control algorithms based on six-step commutation and FOC are studied. Two variants of the six-step commutation braking control, namely, half-bridge commutation and full-bridge commutation, are discussed and compared, which shows that the full-bridge commutation could better explore the potential of the back electro-motive forces （EMF）, thus can deliver higher efficiency and smaller current ripple. The FOC braking is analyzed with the phasor diagrams. At a given motor speed, the motor turns from the regenerative braking mode into the plug braking mode if the braking torque exceeds a certain limit, which is proportional to the motor speed. Tests in the dynamometer show that a smooth control could be realized by FOC driving control and the highest efficiency and the smallest current ripple could be achieved by FOC braking control, compared to six-step commutation braking control. Therefore, FOC braking is selected as the braking control algorithm for electric vehicles. The proposed research ensures a good motor control performance while maintaining low cost and high reliability.
基金Supported by Guangdong Provincial Science and Technology Planning Project of China(Grant Nos.2013B010402006,2013B010405007,2013B090600024)
文摘Coasting in gear is a common driving mode for the conventional vehicle equipped with the internal combustion engine（ICE）, and the assistant braking function of ICE is utilized to decelerate the vehicle in this mode. However, the electric vehicle（EV） does not have this feature in the coasting mode due to the relatively small inertia of the driving motor, so it will cause the driver cannot obtain the similar driving feeling to that of the conventional vehicle, and even a traffic accident may occur if the driver cannot immediately adapt to the changes. In this paper, the coasting control for EV is researched based on the driving feeling. A conventional vehicle equipped with continuously variable transmission（CVT） is taken as the reference vehicle, and the combined simulation model of EV is established based on AVL CRUISE and MATLAB/Simulink. The torque characteristic of the CVT output shaft is measured in coasting mode, and the data are smoothed and fitted to a polynomial curve. For the EV in coasting mode, if the state of charge（SOC） of the battery is below 95%, the polynomial curve is used as the control target for the torque characteristic of the driving motor, otherwise, the required torque is replaced by hydraulic braking torque to keep the same deceleration. The co-simulation of Matlab/Simulink/Stateflow and AVL CRUISE, as well as the hardware-in-loop experiment combined with d SPACE are carried out to verify the effectiveness and the real-time performance of the control algorithm. The results show that the EV with coasting braking control system has similar driving feeling to that of the reference vehicle, meanwhile, the battery SOC can be increased by 0.036% and 0.021% in the initial speed of 100 km/h and 50 km/h, respectively. The proposed control algorithm for EV is beneficial to improve the driving feeling in coasting mode, and it also makes the EV has the assistant braking function.
文摘This paper addresses the co-design problem of decentralized dynamic event-triggered communication and active suspension control for an in-wheel motor driven electric vehicle equipped with a dynamic damper. The main objective is to simultaneously improve the desired suspension performance caused by various road disturbances and alleviate the network resource utilization for the concerned in-vehicle networked suspension system. First, a T-S fuzzy active suspension model of an electric vehicle under dynamic damping is established. Second,a novel decentralized dynamic event-triggered communication mechanism is developed to regulate each sensor's data transmissions such that sampled data packets on each sensor are scheduled in an independent manner. In contrast to the traditional static triggering mechanisms, a key feature of the proposed mechanism is that the threshold parameter in the event trigger is adjusted adaptively over time to reduce the network resources occupancy. Third, co-design criteria for the desired event-triggered fuzzy controller and dynamic triggering mechanisms are derived. Finally, comprehensive comparative simulation studies of a 3-degrees-of-freedom quarter suspension model are provided under both bump road disturbance and ISO-2631 classified random road disturbance to validate the effectiveness of the proposed co-design approach. It is shown that ride comfort can be greatly improved in either road disturbance case and the suspension deflection, dynamic tyre load and actuator control input are all kept below the prescribed maximum allowable limits, while simultaneously maintaining desirable communication efficiency.
基金Supported by the National Natural Science Foundation of China(51105197,51305198,11372129)the Project Funded by the Priority Academic Program Department of Jiangsu Higher Education Instructions
文摘The principle of electric braking system is analyzed and an anti-skid braking system based on the slip rate control is proposed.The fuzzy-PID controller with parameter self-adjustment feature is designed for the anti-skid braking system.The dynamic model of aircraft ground braking is established in the simulation environment of MATLAB/SIMULINK,and simulation results of dry runway and wet runway are presented.The results show that the fuzzy-PID controller with parameter self-adjustment feature for the electric anti-skid braking system keeps working in the state of stability and the brake efficiencies are increased to 93%on dry runway and 82%on wet runway respectively.
基金supported by the National Nature Science Foundation(U1664263)National Key R&D Program of China(2016YFB0101102)。
文摘In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.
基金supported by the National Natural Science Foundation of China (No. 51375229)
文摘Electrically controlled rotor （ECR） system has the potential to enhance the rotor perfor- mance by applying higher harmonic flap inputs. In order to explore the feasibility and effectiveness for ECR performance enhancement using closed-loop control method, firstly, an ECR rotor performance analysis model based on helicopter flight dynamic model is established, which can reflect the performance characteristics of ECR helicopter at high advance ratio. Based on the simulation platform, an active control method named adaptive T-matrix algorithm is adopted to explore the feasibility and effectiveness for ECR performance enhancement. The simulation results verify the effectiveness of this closed-loop control method. For the sample ECR helicopter, about 3% rotor power reduction is obtained with the optimum 2/rev flap inputs at the advance ratio of 0.34. And through analyzing the distributions of attack of angle and drag in rotor disk, the underlying physical essence of ECR power reduction is cleared. Furthermore, the influence of the key control parameters, including convergence factor and weighting matrix, on the effectiveness of closed-loop control for ECR performance enhancement is explored. Some useful results are summarized, which can be used to direct the future active control law design of ECR performance enhancement.
基金supported by National Hi-tech Research and Development Program of China(863 Program,No.2001AA501200,2003AA501200).
文摘In parallel hybrid electrical vehicle(PHEV)equipped with automatic mechanical transmission(AMT),the driving smoothness and the clutch abrasion are the primary considerations for powertrain control during gearshift and clutch operation.To improve these performance indexes of PHEV,a coordinated control system is proposed through the analyzing of HEV powertrain dynamic characteristics.Using the method of minimum principle,the input torque of transmission is optimized to improve the driving smoothness of vehicle.Using the methods of fuzzy logic and fuzzy-PID,the engaging speed of clutch and the throttle opening of engine are manipulated to ensure the smoothness of clutch engagement and reduce the abrasion of clutch friction plates.The motor provides the difference between the required input torque of transmission and the torque transmitted through clutch plates.Results of simulation and experiments show that the proposed control strategy performs better than the contrastive control system,the smoothness of driving and the abrasion of clutch can be improved simultaneously.
