Unmanned Aerial Vehicle(UAV)swarm collaboration enhances mission effectiveness.However,fixed-wing UAV swarm flights face collaborative safety control problems within a limited airspace in complex environments.Aimed at...Unmanned Aerial Vehicle(UAV)swarm collaboration enhances mission effectiveness.However,fixed-wing UAV swarm flights face collaborative safety control problems within a limited airspace in complex environments.Aimed at the cooperative control problem of fixed-wing UAV swarm flights under the airspace constraints of a virtual tube in a complex environment,this paper proposes a behavior-based distributed control method for fixed-wing UAV swarm considering flight safety constraints.Considering the fixed-wing UAV swarm flight problem in complex environment,a virtual tube model based on generator curve is established.The tube keeping,centerline tracking and flight safety behavioral control strategies of the UAV swarm are designed to ensure that the UAV swarm flies along the inside of the virtual tube safety and does not go beyond its boundary.On this basis,a maneuvering decision-making method based on behavioral fusion is proposed to ensure the safe flight of UAV swarm in the restricted airspace.This cooperative control method eliminates the need for respective pre-planned trajectories,reduces communication requirements,and achieves a high level of intelligence.Simulation results show that the proposed behaviorbased UAV swarm cooperative control method is able to make the fixed-wing UAV swarm,which is faster and unable to hover,fly along the virtual tube airspace under various virtual tube shapes and different swarm sizes,and the spacing between the UAVs is larger than the minimum safe distance during the flight.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
Feedforward control is one of the most effective control techniques to increase the robot’s tracking accuracy.However,most of the dynamic models used in the feedforward controllers are linearly simplified such that t...Feedforward control is one of the most effective control techniques to increase the robot’s tracking accuracy.However,most of the dynamic models used in the feedforward controllers are linearly simplified such that the nonlinear and time-varying characteristics of dynamics in the workspace are ignored.In this paper,an iterative tuning method for feedforward control of parallel manipulators by taking nonlinear dynamics into account is proposed.Based on the robot rigid-body dynamic model,a feedforward controller considering the dynamic nonlinearity is presented.An iterative tuning method is given to iteratively update the feedforward controller by minimizing the root mean square(RMS)of the joint errors at each cycle.The effectiveness and extrapolation capability of the proposed method are validated through the experiments on a 2-DOF parallel manipulator.This research proposes an iterative tuning method for feedforward control of parallel manipulators considering nonlinear dynamics,which has better extrapolation capability in the whole workspace of manipulators.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
In the aerospace industry,double-sided friction stir welding has gradually become a crucial solid-state welding technology for rocket manufacturing.During the welding process,the welding equipment on both sides may en...In the aerospace industry,double-sided friction stir welding has gradually become a crucial solid-state welding technology for rocket manufacturing.During the welding process,the welding equipment on both sides may encounter complex conditions involving unsynchronized collaborative movements.The resulting bending stress and destructive vibration affect workpiece processing quality.Therefore,this study proposes an adaptive admittance-based dual-robot collaborative forging force control method for double-sided friction stir welding.Specifically,the following steps are required:First,we analyzed the mechanism model of the hybrid robot and indirectly estimated the forging force value of friction stir welding using the Jacobian matrix of the hybrid robot.Second,an adaptive variable admittance controller was designed based on the reference admittance model with ideal stiffness.Subsequently,an adaptive variable admittance controller was applied to the dual-machine hybrid robot.By adjusting the welding trajectory and correcting the position error,the forging force was corrected,allowing adaptive tracking control of the forging force in complex environments.Finally,we conducted double-sided friction stir welding experiments to compare and verify the effectiveness of the adaptive tracking control algorithm for the forging force.展开更多
Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper ...Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper proposes a phase-split power decoupling unbalanced compensation strategy based load balancing strategy for 3P4L based M-LVDC.Firstly,the topology and operation principle of the 3P4L-based M-LVDC system is introduced,and quasi-proportional resonant(QPR)based phase-split power current control for the 3P4L converter is proposed.Secondly,a load-balancing control strategy considering unbalanced compensation for 3P4L-based MLVDC is presented,in which the control diagrams for each 3P4L-based converter are detailed.The core idea of the proposed strategy is to comprehensively consider the imbalance compensation and load rate balancing between the two areas to calculate the split-phase power and current reference values of each 3P4L converter and achieve the static error-free tracking of the reference values through the QPR current inner-loop control.These reference values are then tracked with zero steady-state error using QPR current inner-loop control.Finally,the effectiveness of the proposed control strategy is verified through a 3P4L M-LVDC case study conducted on the PSCAD/EMTDC software.Theresults indicate that the proposed method not only can reduce the three-phase imbalance degrees from>20% to<0.5%,but also achieve excellent balanced load rates,with the load-rate difference smaller than 1.5%.展开更多
The wireless intelligent water distributor is an emerging technology increasingly applied in oilfields to enhance oil recovery.Although the system has many advantages,the high energy consumption of its integrated cont...The wireless intelligent water distributor is an emerging technology increasingly applied in oilfields to enhance oil recovery.Although the system has many advantages,the high energy consumption of its integrated control valve hinders its adoption in long-term applications.However,existing studies have not sufficiently captured the mechanical characteristics of forces acting on the spool,particularly under the influence of multiple coupled factors,such as fit clearance,deflection,and fluid-structure interaction,which limit the ability to accurately assess energy consumption.To address this gap,this study develops a comprehensive energy consumption model of the control valve,specifically addressing the design of fit clearance,a critical factor influencing energy efficiency.Utilizing a loosely coupled fluid-structure interaction algorithm,we established a mechanical model of the spool to investigate the fluid-solid interaction mechanisms within the fit clearance.For the first time,the effects of contact friction on energy consumption are incorporated.An optimization algorithm was then applied to determine the optimal fit clearance by balancing low friction and minimal leakage.The validity of our numerical model was confirmed through comparison with both theoretical and experimental results.Our results demonstrate that the fit clearance has a pronounced impact on the valve's energy usage:the total maximum energy consumption for one full stroke with a 0.05 mm clearance is 3.33%higher than with a 0.25 mm clearance.When the spool is independently driven,this value is 7.21%.The optimal fit clearance is determined to be 0.127 mm.These results can improve the overall performance and extend the service life of intelligent water distributors.The findings and models developed in this study provide essential theoretical support and practical strategies for optimizing control valve energy consumption.展开更多
The integrated energy systems(IESs)offer a practical solution for achieving low-carbon targets in residential buildings.However,IES encounters several challenges related to increased energy consumption and costs due t...The integrated energy systems(IESs)offer a practical solution for achieving low-carbon targets in residential buildings.However,IES encounters several challenges related to increased energy consumption and costs due to fluctuations in renewable energy generation.Leveraging building flexibility to address these power fluctuations within IES is a promising strategy,which requires coordinated control between air-conditioning systems and other IES components.This study proposes a cross-time-scale control framework that contains optimal scheduling and on-the-fly flexible control to reduce the cost impacts of a residential IES system equipped with photovoltaic(PV)panels,batteries,a heat pump,and a domestic hot water tank.The method involves three key steps:solar irradiance prediction,day-ahead optimal scheduling of energy storage,and intra-day flexible control of the heat pump.The method is validated through a high-fidelity residential building model with actual weather and energy usage data in Frankfurt,Germany.Results reveal that the proposed method limits the cost increase to just 2.67% compared to the day-ahead schedule,whereas the cost could increase by 7.39% without the flexible control.Additionally,computational efficiency is enhanced by transforming the mixed-integer programming(MIP)into nonlinear programming(NLP)problem via introducing action-exclusive constraints.This approach offers valuable support for residential IES operations.展开更多
The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as diff...The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.展开更多
Innovating distillation technology to improve the efficiency of distillation equipment,reduce energy consumption,and increase product purity is an important challenge for the rapid development of the distillation indu...Innovating distillation technology to improve the efficiency of distillation equipment,reduce energy consumption,and increase product purity is an important challenge for the rapid development of the distillation industry.In this paper,steady-state simulations are developed for the separated isopropanol and water systems,and the sensitive temperature stage locations are determined using sensitivity and singular value decomposition(SVD).An open-loop steady-state gain analysis of the isopropanol/water system was performed,and a series of dynamic control schemes were designed and optimized to resist±10% feed flow disturbances and ±5% feed composition disturbances,comparing the performance of the control schemes one by one through IAE error analysis.The results show that the side-stream extractive distillation separation of isopropanol and water system using a single temperature fixed reflux ratio control loop suffers from a large product shift problem.One of the key control loops is to control the isopropanol purity by controlling the bottom of the column flow rate,and the scheme performs well under both single-temperature control and dual-temperature control,effectively resisting ±10% feed flow disturbances and ±5% feed composition disturbances.The improvement of product purity can be seen from the compone nt controllers play an important role,while the feed-fo rward effect under certain conditions can also enable the system to quickly restore stability and improve the system response speed.展开更多
This paper addresses the lane-keeping control problem for autonomous ground vehicles subject to input saturation and uncertain system parameters.An enhanced adaptive terminal sliding mode based prescribed performance ...This paper addresses the lane-keeping control problem for autonomous ground vehicles subject to input saturation and uncertain system parameters.An enhanced adaptive terminal sliding mode based prescribed performance control scheme is proposed,which enables the lateral position error of the vehicle to be kept within the prescribed performance boundaries all the time.This is achieved by firstly introducing an improved performance function into the controller design such that the stringent initial condition requirements can be relaxed,which further allows the global prescribed performance control result,and then,developing a multivariable adaptive terminal sliding mode based controller such that both input saturation and parameter uncertainties are handled effectively,which further ensures the robust lane-keeping control.Finally,the proposed control strategy is validated through numerical simulations,demonstrating its effectiveness.展开更多
In the existing impact time control guidance (ITCG) laws for moving-targets, the effects of time-varying velocity caused by aerodynamics and gravity cannot be effectively con-sidered. Therefore, an ITCG with field-of-...In the existing impact time control guidance (ITCG) laws for moving-targets, the effects of time-varying velocity caused by aerodynamics and gravity cannot be effectively con-sidered. Therefore, an ITCG with field-of-view (FOV) constraints based on biased proportional navigation guidance (PNG) is developed in this paper. The remaining flight time (time-to-go) estimation method is derived considering aerodynamic force and gravity. The number of differential equations is reduced and the integration step is increased by changing the integral variable, which makes it possible to obtain time-to-go through integration. An impact time controller with FOV constraints is proposed by analyzing the influence of the biased term on time-to-go and FOV constraint. Then, numerical simulations are performed to verify the correctness and superiority of the method.展开更多
A drag-free satellite is an important platform for space-borne gravitational wave(GW)observation.To achieve the high-precision control of a drag-free satellite in practical engineering,an accurate dynamic model is ess...A drag-free satellite is an important platform for space-borne gravitational wave(GW)observation.To achieve the high-precision control of a drag-free satellite in practical engineering,an accurate dynamic model is essential.This paper presents a nonlinear model of the electrostatic effect between a satellite and a test mass(TM),and designs a model predictive controller based on the drag-free satellite model with the nonlinear electrostatic effect.To determine the analytical form of the electrostatic effect,a comprehensive theoretical analysis is performed for gravitational reference sensors(GRSs).An electrostatic force and a torque are simulated with the displacement as a varying parameter through a commercial software.Then,the results are fitted to derive the nonlinear expressions of the electrostatic effect.The model predictive controllers based on the models with the nonlinear and linear electrostatic effects are designed in the capture mode.Finally,the control results are given to show the advantages of the nonlinear electrostatic effect.展开更多
Liquid cooling through a cold plate offers an efficient solution for battery thermal management.Excellent flow and heat transfer performance can be obtained by optimizing the flow channel structure of the cold plate u...Liquid cooling through a cold plate offers an efficient solution for battery thermal management.Excellent flow and heat transfer performance can be obtained by optimizing the flow channel structure of the cold plate using the topology optimization method.However,due to the uneven channel width of the optimized cold plate,there are some difficulties in processing,which affect its practical application in battery thermal management.In this study,the length scale control method is applied to a topology-optimized cold plate.An optimized cold plate considering length scale control is designed and processed,and its experimental results of flow and heat transfer are compared with those of a traditional cold plate and an optimized cold plate without length scale control.Results show that the relative deviations between the numerical and experimental results with length scale control are within 5%and 8%for temperature and pressure drop,respectively.The flow channel structure of the cold plate with length scale control is simpler and easier to process than that of the cold plate without length scale control.When the inlet velocity is 0.23 m/s,the maximum temperature,maximum temperature difference,and pressure drop of the cold plate with length scale control are 5.7 K,4.4 K,and 0.56 Pa lower than those of the traditional cold plate,respectively.This study provides valuable insights and practical guidance for the manufacturing and implementation of topology-optimized cold plates in battery thermal management systems.展开更多
Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybr...Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations.展开更多
This paper proposes a new approach to eliminate aerodynamic lift oscillation,called the Dominant Sector Individual Blade Control(DS-IBC)method for rigid rotor helicopters.An Advancing Blade Concept(ABC)rotor model for...This paper proposes a new approach to eliminate aerodynamic lift oscillation,called the Dominant Sector Individual Blade Control(DS-IBC)method for rigid rotor helicopters.An Advancing Blade Concept(ABC)rotor model for aerodynamic analysis based on the free-wake method is applied.DS-IBC avoids applying active control on the rotor's retreating side by employing and restricting active control inputs to a sector area of the rotor disc.Outside this sector,only primary collective and cyclic pitch control are used.Each blade takes turns entering the sector,creating a“relay”active control form to ensure continuous control inputs.The method also includes outer-trim and inner-trim iteration modules.Results show that DS-IBC can eliminate aerodynamic lift oscillation using much smaller control inputs than the sine-trim method.By focusing active control on the rotor's advancing side,DS-IBC improves the effective lift-to-drag ratio and reduces the implementation difficulty of active rotor control for aerodynamic oscillation elimination,especially at a large lift-offset.展开更多
This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relativ...This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.展开更多
0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly ...0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly prominent.China has implemented and completed several largescale land infilling and excavation projects(Figure 1),which have become the main way to increase land resources and expand construction land.展开更多
This article investigates the robust current tracking control problem of three-phase grid-connected inverters with LCL filter under external disturbance by a dynamic state feedback control method.First,this paper cons...This article investigates the robust current tracking control problem of three-phase grid-connected inverters with LCL filter under external disturbance by a dynamic state feedback control method.First,this paper constructs an internal model to learn the information of the states and input of the grid-connected inverter under steady state.Second,by utilizing the internal model principle,the paper turns the tracking control problem into the robust stabilization control problem based on some appropriate coordinate transformations.Then,The paper designs a dynamics state feedback control law to deal with this robust stabilization problem,and thus the solution of the robust current tracking control problem of three-phase grid-connected inverters can be obtained.This control method can ensure the asymptotic stability of the closedloop system.Finally,the paper illustrates the effectiveness of the proposed control approach through several groups of simulations,and compares it with the feedforward control method to verify the robustness of the proposed control method to uncertain parameters.展开更多
Aiming to solve the steering instability and hysteresis of agricultural robots in the process of movement,a fusion PID control method of particle swarm optimization(PSO)and genetic algorithm(GA)was proposed.The fusion...Aiming to solve the steering instability and hysteresis of agricultural robots in the process of movement,a fusion PID control method of particle swarm optimization(PSO)and genetic algorithm(GA)was proposed.The fusion algorithm took advantage of the fast optimization ability of PSO to optimize the population screening link of GA.The Simulink simulation results showed that the convergence of the fitness function of the fusion algorithm was accelerated,the system response adjustment time was reduced,and the overshoot was almost zero.Then the algorithm was applied to the steering test of agricultural robot in various scenes.After modeling the steering system of agricultural robot,the steering test results in the unloaded suspended state showed that the PID control based on fusion algorithm reduced the rise time,response adjustment time and overshoot of the system,and improved the response speed and stability of the system,compared with the artificial trial and error PID control and the PID control based on GA.The actual road steering test results showed that the PID control response rise time based on the fusion algorithm was the shortest,about 4.43 s.When the target pulse number was set to 100,the actual mean value in the steady-state regulation stage was about 102.9,which was the closest to the target value among the three control methods,and the overshoot was reduced at the same time.The steering test results under various scene states showed that the PID control based on the proposed fusion algorithm had good anti-interference ability,it can adapt to the changes of environment and load and improve the performance of the control system.It was effective in the steering control of agricultural robot.This method can provide a reference for the precise steering control of other robots.展开更多
基金co-supported by the National Natural Science Foundation of China(No.61903350)the Ministry of Education industry-university-research innovation project,China(No.2021ZYA02002)the Beijing Institute of Technology Research Fund Program for Young Scholars,China(No.3010011182130)。
文摘Unmanned Aerial Vehicle(UAV)swarm collaboration enhances mission effectiveness.However,fixed-wing UAV swarm flights face collaborative safety control problems within a limited airspace in complex environments.Aimed at the cooperative control problem of fixed-wing UAV swarm flights under the airspace constraints of a virtual tube in a complex environment,this paper proposes a behavior-based distributed control method for fixed-wing UAV swarm considering flight safety constraints.Considering the fixed-wing UAV swarm flight problem in complex environment,a virtual tube model based on generator curve is established.The tube keeping,centerline tracking and flight safety behavioral control strategies of the UAV swarm are designed to ensure that the UAV swarm flies along the inside of the virtual tube safety and does not go beyond its boundary.On this basis,a maneuvering decision-making method based on behavioral fusion is proposed to ensure the safe flight of UAV swarm in the restricted airspace.This cooperative control method eliminates the need for respective pre-planned trajectories,reduces communication requirements,and achieves a high level of intelligence.Simulation results show that the proposed behaviorbased UAV swarm cooperative control method is able to make the fixed-wing UAV swarm,which is faster and unable to hover,fly along the virtual tube airspace under various virtual tube shapes and different swarm sizes,and the spacing between the UAVs is larger than the minimum safe distance during the flight.
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 National Natural Science Foundation of China(Grant No.52375502)EU H2020 MSCA R&I Programme(Grant No.101022696).
文摘Feedforward control is one of the most effective control techniques to increase the robot’s tracking accuracy.However,most of the dynamic models used in the feedforward controllers are linearly simplified such that the nonlinear and time-varying characteristics of dynamics in the workspace are ignored.In this paper,an iterative tuning method for feedforward control of parallel manipulators by taking nonlinear dynamics into account is proposed.Based on the robot rigid-body dynamic model,a feedforward controller considering the dynamic nonlinearity is presented.An iterative tuning method is given to iteratively update the feedforward controller by minimizing the root mean square(RMS)of the joint errors at each cycle.The effectiveness and extrapolation capability of the proposed method are validated through the experiments on a 2-DOF parallel manipulator.This research proposes an iterative tuning method for feedforward control of parallel manipulators considering nonlinear dynamics,which has better extrapolation capability in the whole workspace of manipulators.
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 Key R&D program of China(Grant No.2019YFA0709004)National Natural Science Foundation of China(Grant Nos.52325501,52175025).
文摘In the aerospace industry,double-sided friction stir welding has gradually become a crucial solid-state welding technology for rocket manufacturing.During the welding process,the welding equipment on both sides may encounter complex conditions involving unsynchronized collaborative movements.The resulting bending stress and destructive vibration affect workpiece processing quality.Therefore,this study proposes an adaptive admittance-based dual-robot collaborative forging force control method for double-sided friction stir welding.Specifically,the following steps are required:First,we analyzed the mechanism model of the hybrid robot and indirectly estimated the forging force value of friction stir welding using the Jacobian matrix of the hybrid robot.Second,an adaptive variable admittance controller was designed based on the reference admittance model with ideal stiffness.Subsequently,an adaptive variable admittance controller was applied to the dual-machine hybrid robot.By adjusting the welding trajectory and correcting the position error,the forging force was corrected,allowing adaptive tracking control of the forging force in complex environments.Finally,we conducted double-sided friction stir welding experiments to compare and verify the effectiveness of the adaptive tracking control algorithm for the forging force.
基金supported by the key technology project of China Southern Power Grid Corporation(GZKJXM20220041)partly by theNational Key Research and Development Plan(2022YFE0205300).
文摘Aiming at the challenge of complex load balancing coordination for a three-phase four-leg(3P4L)based multi-ended low voltage flexible DC distribution system(M-LVDC)considering unbalanced power compensation,this paper proposes a phase-split power decoupling unbalanced compensation strategy based load balancing strategy for 3P4L based M-LVDC.Firstly,the topology and operation principle of the 3P4L-based M-LVDC system is introduced,and quasi-proportional resonant(QPR)based phase-split power current control for the 3P4L converter is proposed.Secondly,a load-balancing control strategy considering unbalanced compensation for 3P4L-based MLVDC is presented,in which the control diagrams for each 3P4L-based converter are detailed.The core idea of the proposed strategy is to comprehensively consider the imbalance compensation and load rate balancing between the two areas to calculate the split-phase power and current reference values of each 3P4L converter and achieve the static error-free tracking of the reference values through the QPR current inner-loop control.These reference values are then tracked with zero steady-state error using QPR current inner-loop control.Finally,the effectiveness of the proposed control strategy is verified through a 3P4L M-LVDC case study conducted on the PSCAD/EMTDC software.Theresults indicate that the proposed method not only can reduce the three-phase imbalance degrees from>20% to<0.5%,but also achieve excellent balanced load rates,with the load-rate difference smaller than 1.5%.
基金supported by China Scholarship Council(CSC)(No.202306440123).
文摘The wireless intelligent water distributor is an emerging technology increasingly applied in oilfields to enhance oil recovery.Although the system has many advantages,the high energy consumption of its integrated control valve hinders its adoption in long-term applications.However,existing studies have not sufficiently captured the mechanical characteristics of forces acting on the spool,particularly under the influence of multiple coupled factors,such as fit clearance,deflection,and fluid-structure interaction,which limit the ability to accurately assess energy consumption.To address this gap,this study develops a comprehensive energy consumption model of the control valve,specifically addressing the design of fit clearance,a critical factor influencing energy efficiency.Utilizing a loosely coupled fluid-structure interaction algorithm,we established a mechanical model of the spool to investigate the fluid-solid interaction mechanisms within the fit clearance.For the first time,the effects of contact friction on energy consumption are incorporated.An optimization algorithm was then applied to determine the optimal fit clearance by balancing low friction and minimal leakage.The validity of our numerical model was confirmed through comparison with both theoretical and experimental results.Our results demonstrate that the fit clearance has a pronounced impact on the valve's energy usage:the total maximum energy consumption for one full stroke with a 0.05 mm clearance is 3.33%higher than with a 0.25 mm clearance.When the spool is independently driven,this value is 7.21%.The optimal fit clearance is determined to be 0.127 mm.These results can improve the overall performance and extend the service life of intelligent water distributors.The findings and models developed in this study provide essential theoretical support and practical strategies for optimizing control valve energy consumption.
基金supported by the National Key Research and Development Program of China(2022YFB4200902)。
文摘The integrated energy systems(IESs)offer a practical solution for achieving low-carbon targets in residential buildings.However,IES encounters several challenges related to increased energy consumption and costs due to fluctuations in renewable energy generation.Leveraging building flexibility to address these power fluctuations within IES is a promising strategy,which requires coordinated control between air-conditioning systems and other IES components.This study proposes a cross-time-scale control framework that contains optimal scheduling and on-the-fly flexible control to reduce the cost impacts of a residential IES system equipped with photovoltaic(PV)panels,batteries,a heat pump,and a domestic hot water tank.The method involves three key steps:solar irradiance prediction,day-ahead optimal scheduling of energy storage,and intra-day flexible control of the heat pump.The method is validated through a high-fidelity residential building model with actual weather and energy usage data in Frankfurt,Germany.Results reveal that the proposed method limits the cost increase to just 2.67% compared to the day-ahead schedule,whereas the cost could increase by 7.39% without the flexible control.Additionally,computational efficiency is enhanced by transforming the mixed-integer programming(MIP)into nonlinear programming(NLP)problem via introducing action-exclusive constraints.This approach offers valuable support for residential IES operations.
基金This work described herein was supported by the Program of China Scholarship Council(202206430008)the National Natural Science Foundation of China(NSFC)(52074300 and 52304111)+1 种基金the Yueqi Young Scholars Project of China University of Mining and Technology Beijing(2602021RC84)the Guizhou province science and technology planning project([2020]3007 and[2020]2Y019).
文摘The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.
基金the Key Research and Development Plan of Shandong Province (Major Scientific and Technological Innovation Project) (2021ZDSYS24)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing (Yantai) (AMGM2023A09)the Open Project Program of Fujian Universities Engineering Research Center of Reactive Distillation Technology (RDRC202204), Fuzhou University。
文摘Innovating distillation technology to improve the efficiency of distillation equipment,reduce energy consumption,and increase product purity is an important challenge for the rapid development of the distillation industry.In this paper,steady-state simulations are developed for the separated isopropanol and water systems,and the sensitive temperature stage locations are determined using sensitivity and singular value decomposition(SVD).An open-loop steady-state gain analysis of the isopropanol/water system was performed,and a series of dynamic control schemes were designed and optimized to resist±10% feed flow disturbances and ±5% feed composition disturbances,comparing the performance of the control schemes one by one through IAE error analysis.The results show that the side-stream extractive distillation separation of isopropanol and water system using a single temperature fixed reflux ratio control loop suffers from a large product shift problem.One of the key control loops is to control the isopropanol purity by controlling the bottom of the column flow rate,and the scheme performs well under both single-temperature control and dual-temperature control,effectively resisting ±10% feed flow disturbances and ±5% feed composition disturbances.The improvement of product purity can be seen from the compone nt controllers play an important role,while the feed-fo rward effect under certain conditions can also enable the system to quickly restore stability and improve the system response speed.
基金supported in part by the National Key Research and Development Program of China under Grant 2023YFA1011803in part by Natural Science Foundation of Chongqing,China under Grant CSTB2023NSCQ-MSX0588+2 种基金in part by the Fundamental Research Funds for the Central Universities,China under Grant 2023CDJKYJH047in part by the National Natural Science Foundation of China under Grant 62273064,Grant 61991400,Grant 61991403,Grant 61933012,Grant 62250710167,Grant 62203078in part by Innovation Support Program for International Students Returning to China under Grant cx2022016.
文摘This paper addresses the lane-keeping control problem for autonomous ground vehicles subject to input saturation and uncertain system parameters.An enhanced adaptive terminal sliding mode based prescribed performance control scheme is proposed,which enables the lateral position error of the vehicle to be kept within the prescribed performance boundaries all the time.This is achieved by firstly introducing an improved performance function into the controller design such that the stringent initial condition requirements can be relaxed,which further allows the global prescribed performance control result,and then,developing a multivariable adaptive terminal sliding mode based controller such that both input saturation and parameter uncertainties are handled effectively,which further ensures the robust lane-keeping control.Finally,the proposed control strategy is validated through numerical simulations,demonstrating its effectiveness.
基金supported by the National Natural Science Foundation of China(U21B2028).
文摘In the existing impact time control guidance (ITCG) laws for moving-targets, the effects of time-varying velocity caused by aerodynamics and gravity cannot be effectively con-sidered. Therefore, an ITCG with field-of-view (FOV) constraints based on biased proportional navigation guidance (PNG) is developed in this paper. The remaining flight time (time-to-go) estimation method is derived considering aerodynamic force and gravity. The number of differential equations is reduced and the integration step is increased by changing the integral variable, which makes it possible to obtain time-to-go through integration. An impact time controller with FOV constraints is proposed by analyzing the influence of the biased term on time-to-go and FOV constraint. Then, numerical simulations are performed to verify the correctness and superiority of the method.
基金supported by the National Key Research and Development Program of China(No.2022YFC2204800)the National Natural Science Foundation of China(No.W2433004)the Jiangsu Funding Program for Excellent Postdoctoral Talent of China(No.2024ZB114)。
文摘A drag-free satellite is an important platform for space-borne gravitational wave(GW)observation.To achieve the high-precision control of a drag-free satellite in practical engineering,an accurate dynamic model is essential.This paper presents a nonlinear model of the electrostatic effect between a satellite and a test mass(TM),and designs a model predictive controller based on the drag-free satellite model with the nonlinear electrostatic effect.To determine the analytical form of the electrostatic effect,a comprehensive theoretical analysis is performed for gravitational reference sensors(GRSs).An electrostatic force and a torque are simulated with the displacement as a varying parameter through a commercial software.Then,the results are fitted to derive the nonlinear expressions of the electrostatic effect.The model predictive controllers based on the models with the nonlinear and linear electrostatic effects are designed in the capture mode.Finally,the control results are given to show the advantages of the nonlinear electrostatic effect.
基金supported by the National Natural Science Foundation of China(No.52206271)Guangxi Science and Technology Major Program(GK-AA23062070)+2 种基金the National Natural Science Foundation of China(No.52306266)the Key Project of Natural Science Funds of Tianjin City(No.24JCZDJC01060)funded by the Key Laboratory of Shallow Geothermal Energy,Ministry of Natural Resources of the People’s Republic of China(No.KLSGE202401-04).
文摘Liquid cooling through a cold plate offers an efficient solution for battery thermal management.Excellent flow and heat transfer performance can be obtained by optimizing the flow channel structure of the cold plate using the topology optimization method.However,due to the uneven channel width of the optimized cold plate,there are some difficulties in processing,which affect its practical application in battery thermal management.In this study,the length scale control method is applied to a topology-optimized cold plate.An optimized cold plate considering length scale control is designed and processed,and its experimental results of flow and heat transfer are compared with those of a traditional cold plate and an optimized cold plate without length scale control.Results show that the relative deviations between the numerical and experimental results with length scale control are within 5%and 8%for temperature and pressure drop,respectively.The flow channel structure of the cold plate with length scale control is simpler and easier to process than that of the cold plate without length scale control.When the inlet velocity is 0.23 m/s,the maximum temperature,maximum temperature difference,and pressure drop of the cold plate with length scale control are 5.7 K,4.4 K,and 0.56 Pa lower than those of the traditional cold plate,respectively.This study provides valuable insights and practical guidance for the manufacturing and implementation of topology-optimized cold plates in battery thermal management systems.
文摘Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations.
基金supported by the National Natural Science Foundation of China(No.12372229)the Aeronautical Science Foundation of China(No.2020Z006063001)+1 种基金the Science and Technology on Rotorcraft Aeromechanics Laboratory Foundation,China(No.61422202110)the Fundamental Research Funds for the Central Universities of China(No.DUT22LK12)。
文摘This paper proposes a new approach to eliminate aerodynamic lift oscillation,called the Dominant Sector Individual Blade Control(DS-IBC)method for rigid rotor helicopters.An Advancing Blade Concept(ABC)rotor model for aerodynamic analysis based on the free-wake method is applied.DS-IBC avoids applying active control on the rotor's retreating side by employing and restricting active control inputs to a sector area of the rotor disc.Outside this sector,only primary collective and cyclic pitch control are used.Each blade takes turns entering the sector,creating a“relay”active control form to ensure continuous control inputs.The method also includes outer-trim and inner-trim iteration modules.Results show that DS-IBC can eliminate aerodynamic lift oscillation using much smaller control inputs than the sine-trim method.By focusing active control on the rotor's advancing side,DS-IBC improves the effective lift-to-drag ratio and reduces the implementation difficulty of active rotor control for aerodynamic oscillation elimination,especially at a large lift-offset.
文摘This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.
基金funded by the Key Research and Development Program of Shaanxi Province(No.2024SFYBXM-669)the National Natural Science Foundation of China(No.42271078)。
文摘0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly prominent.China has implemented and completed several largescale land infilling and excavation projects(Figure 1),which have become the main way to increase land resources and expand construction land.
基金Supported by the Fundamental Research Funds for the Central Universities(2024ZYGXZR047)the National Natural Science Foundation of China(62373156)the Guangdong Basic and Applied Basic Research Foundation(2024A1515011736)。
文摘This article investigates the robust current tracking control problem of three-phase grid-connected inverters with LCL filter under external disturbance by a dynamic state feedback control method.First,this paper constructs an internal model to learn the information of the states and input of the grid-connected inverter under steady state.Second,by utilizing the internal model principle,the paper turns the tracking control problem into the robust stabilization control problem based on some appropriate coordinate transformations.Then,The paper designs a dynamics state feedback control law to deal with this robust stabilization problem,and thus the solution of the robust current tracking control problem of three-phase grid-connected inverters can be obtained.This control method can ensure the asymptotic stability of the closedloop system.Finally,the paper illustrates the effectiveness of the proposed control approach through several groups of simulations,and compares it with the feedforward control method to verify the robustness of the proposed control method to uncertain parameters.
文摘Aiming to solve the steering instability and hysteresis of agricultural robots in the process of movement,a fusion PID control method of particle swarm optimization(PSO)and genetic algorithm(GA)was proposed.The fusion algorithm took advantage of the fast optimization ability of PSO to optimize the population screening link of GA.The Simulink simulation results showed that the convergence of the fitness function of the fusion algorithm was accelerated,the system response adjustment time was reduced,and the overshoot was almost zero.Then the algorithm was applied to the steering test of agricultural robot in various scenes.After modeling the steering system of agricultural robot,the steering test results in the unloaded suspended state showed that the PID control based on fusion algorithm reduced the rise time,response adjustment time and overshoot of the system,and improved the response speed and stability of the system,compared with the artificial trial and error PID control and the PID control based on GA.The actual road steering test results showed that the PID control response rise time based on the fusion algorithm was the shortest,about 4.43 s.When the target pulse number was set to 100,the actual mean value in the steady-state regulation stage was about 102.9,which was the closest to the target value among the three control methods,and the overshoot was reduced at the same time.The steering test results under various scene states showed that the PID control based on the proposed fusion algorithm had good anti-interference ability,it can adapt to the changes of environment and load and improve the performance of the control system.It was effective in the steering control of agricultural robot.This method can provide a reference for the precise steering control of other robots.
