To improve the resource utilization ratio and shorten the recovery time of the shared path protection with differentiated reliability （SPP-DiR） algorithm, an algorithm called dynamic shared segment protection with d...To improve the resource utilization ratio and shorten the recovery time of the shared path protection with differentiated reliability （SPP-DiR） algorithm, an algorithm called dynamic shared segment protection with differentiated reliability （DSSP-DiR） is proposed for survivable GMPLS networks. In the proposed algorithm, a primary path is dynamically divided into several segments according to the differentiated reliability requirements of the customers. In the SPP-DiR algorithm, the whole primary path should be protected, while in the DSSP- DiR algorithm, only partial segments on the primary path need to be protected, which can reduce more backup bandwidths than that in the SPP-DiR algorithm. Simulation results show that the DSSP-DiR algorithm achieves higher resource utilization ratio, lower protection failure probability, and shorter recovery time than the SPP-DiR algorithm.展开更多
When the maneuverability of a pursuer is not significantly higher than that of an evader,it will be difficult to intercept the evader with only one pursuer.Therefore,this article adopts a two-to-one differential game ...When the maneuverability of a pursuer is not significantly higher than that of an evader,it will be difficult to intercept the evader with only one pursuer.Therefore,this article adopts a two-to-one differential game strategy,the game of kind is generally considered to be angle-optimized,which allows unlimited turns,but these practices do not take into account the effect of acceleration,which does not correspond to the actual situation,thus,based on the angle-optimized,the acceleration optimization and the acceleration upper bound constraint are added into the game for consideration.A two-to-one differential game problem is proposed in the three-dimensional space,and an improved multi-objective grey wolf optimization(IMOGWO)algorithm is proposed to solve the optimal game point of this problem.With the equations that describe the relative motions between the pursuers and the evader in the three-dimensional space,a multi-objective function with constraints is given as the performance index to design an optimal strategy for the differential game.Then the optimal game point is solved by using the IMOGWO algorithm.It is proved based on Markov chains that with the IMOGWO,the Pareto solution set is the solution of the differential game.Finally,it is verified through simulations that the pursuers can capture the escapee,and via comparative experiments,it is shown that the IMOGWO algorithm performs well in terms of running time and memory usage.展开更多
Objective Cerebral palsy(CP)is a prevalent neurodevelopmental disorder acquired during the perinatal period,with periventricular white matter injury(PWMI)serving as its primary pathological hallmark.PWMI is characteri...Objective Cerebral palsy(CP)is a prevalent neurodevelopmental disorder acquired during the perinatal period,with periventricular white matter injury(PWMI)serving as its primary pathological hallmark.PWMI is characterized by the loss of oligodendrocytes(OLs)and the disintegration of myelin sheaths,leading to impaired neural connectivity and motor dysfunction.Neural stem cells(NSCs)represent a promising regenerative source for replenishing lost OLs;however,conventional twodimensional(2D)in vitro culture systems lack the three-dimensional(3D)physiological microenvironment.Microfluidic chip technology has emerged as a powerful tool to overcome this limitation by enabling precise spatial and temporal control over 3D microenvironmental conditions,including the establishment of stable concentration gradients of bioactive molecules.Catalpol,an iridoid glycoside derived from traditional medicinal plants,exhibits dual antioxidant and anti-apoptotic properties.Despite its therapeutic potential,the capacity of catalpol to drive NSC differentiation toward OLs under biomimetic 3D conditions,as well as the underlying molecular mechanisms,remains poorly understood.This study aims to develop a microfluidic-based 3D biomimetic platform to systematically investigate the concentration-dependent effects of catalpol on promoting NSCs-to-OLs differentiation and to elucidate the role of the caveolin-1(Cav-1)signaling pathway in this process.Methods We developed a novel multiplexed microfluidic device featuring parallel microchannels with integrated gradient generators capable of establishing and maintaining precise linear concentration gradients(0-3 g/L catalpol)across 3D NSCs cultures.This platform facilitated the continuous perfusion culture of NSC-derived 3D spheroids,mimicking the dynamic in vivo microenvironment.Real-time cell viability was assessed using Calcein-AM/propidium iodide(PI)dual staining,with fluorescence imaging quantifying live/dead cell ratios.Oligodendrocyte differentiation was evaluated through quantitative reverse transcription polymerase chain reaction(qRT-PCR)for MBP and SOX10 gene expression,complemented by immunofluorescence staining to visualize corresponding protein changes.To dissect the molecular mechanism,the Cav-1-specific pharmacological inhibitor methyl‑β‑cyclodextrin(MCD)was employed to perturb the pathway,and its effects on differentiation markers were analyzed.Results Catalpol demonstrated excellent biocompatibility,with cell viability exceeding 96%across the entire tested concentration range(0-3 g/L),confirming its non-cytotoxic nature.At the optimal concentration of 0-3 g/L,catalpol significantly upregulated both MBP and SOX10 expression(P<0.05,P<0.01),indicating robust promotion of oligodendroglial differentiation.Intriguingly,Cav-1 mRNA expression was progressively downregulated during NSC differentiation into OLs.Further inhibition of Cav-1 with MCD further enhanced this effect,leading to a statistically significant increase in OL-specific gene expression(P<0.05,P<0.01),suggesting Cav-1 acts as a negative regulator of OLs differentiation.Conclusion This study established an integrated microfluidic gradient chip-3D NSC spheroid culture system,which combines the advantages of precise chemical gradient control with physiologically relevant 3D cell culture.The findings demonstrate that 3 g/L catalpol effectively suppresses Cav-1 signaling to drive NSC differentiation into functional OLs.This work not only provides novel insights into the Cav-1-dependent mechanisms of myelination but also delivers a scalable technological platform for future research on remyelination therapies,with potential applications in cerebral palsy and other white matter disorders.The platform’s modular design permits adaptation for screening other neurogenic compounds or investigating additional signaling pathways involved in OLs maturation.展开更多
The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic fu...The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic functions in the unit ball by radial derivative.Then we extend the Sharma's results.展开更多
This paper studies the Smoluchowski–Kramers approximation for a discrete-time dynamical system modeled as the motion of a particle in a force field.We show that the approximation holds for the drift-implicit Euler–M...This paper studies the Smoluchowski–Kramers approximation for a discrete-time dynamical system modeled as the motion of a particle in a force field.We show that the approximation holds for the drift-implicit Euler–Maruyama discretization and derive its convergence rate.In particular,the solution of the discretized system converges to the solution of the first-order limit equation in the mean-square sense,and this convergence is independent of the order in which the mass parameterμand the step size h tend to zero.展开更多
Objective:To evaluate the predictive value of the neutrophil⁃to⁃lymphocyte ratio(NLR)and the systemic immune⁃inflammation index(SII)in predicting patients with anti⁃melanoma differentiation⁃associated gene 5⁃positive(...Objective:To evaluate the predictive value of the neutrophil⁃to⁃lymphocyte ratio(NLR)and the systemic immune⁃inflammation index(SII)in predicting patients with anti⁃melanoma differentiation⁃associated gene 5⁃positive(anti⁃MDA5+)dermatomyositis(DM)develop into the rapidly progressive interstitial lung disease(RPILD).Methods:We retrospectively analyzed the clinical and laboratory data of 124 anti⁃MDA5+DM patients from the First Affiliated Hospital of Nanjing Medical University between March 2019 and September 2023.We identified independent risk factors associated with the development and mortality of RPILD with the Cox regression analysis,and determined the optimal cut⁃off values for predicting adverse outcomes with the receiver operating characteristic(ROC)curve analysis.Results:Among the 124 patients,36 patients(29.03%)developed RPILD,and 39 patients(31.45%)died during the follow⁃up period.The results of multivariate Cox regression analysis showed that the elevated NLR was an independent risk factor for RPILD development,while the elevated SII expression was independently associated with the increased mortality of RPILD.Based on the ROC curve analysis,NLR>6.12 was a predictor for RPILD,and SII>875.79 was associated with increased mortality risk of RPILD.Conclusion:Both NLR and SII are accessible,cost⁃effective,and reliable prognostic indicators for the prognosis of patients with anti⁃MDA5^(+)DM,providing a valuable guidance for clinical management and risk stratification of the disease.展开更多
Dynamic soaring,inspired by the wind-riding flight of birds such as albatrosses,is a biomimetic technique which leverages wind fields to enhance the endurance of unmanned aerial vehicles(UAVs).Achieving a precise soar...Dynamic soaring,inspired by the wind-riding flight of birds such as albatrosses,is a biomimetic technique which leverages wind fields to enhance the endurance of unmanned aerial vehicles(UAVs).Achieving a precise soaring trajectory is crucial for maximizing energy efficiency during flight.Existing nonlinear programming methods are heavily dependent on the choice of initial values which is hard to determine.Therefore,this paper introduces a deep reinforcement learning method based on a differentially flat model for dynamic soaring trajectory planning and optimization.Initially,the gliding trajectory is parameterized using Fourier basis functions,achieving a flexible trajectory representation with a minimal number of hyperparameters.Subsequently,the trajectory optimization problem is formulated as a dynamic interactive process of Markov decision-making.The hyperparameters of the trajectory are optimized using the Proximal Policy Optimization(PPO2)algorithm from deep reinforcement learning(DRL),reducing the strong reliance on initial value settings in the optimization process.Finally,a comparison between the proposed method and the nonlinear programming method reveals that the trajectory generated by the proposed approach is smoother while meeting the same performance requirements.Specifically,the proposed method achieves a 34%reduction in maximum thrust,a 39.4%decrease in maximum thrust difference,and a 33%reduction in maximum airspeed difference.展开更多
This paper presents a mode-switching collaborative defense strategy for spacecraft pursuit-evasiondefense scenarios.In these scenarios,the pursuer tries to avoid the defender while capturing the evader,while the evade...This paper presents a mode-switching collaborative defense strategy for spacecraft pursuit-evasiondefense scenarios.In these scenarios,the pursuer tries to avoid the defender while capturing the evader,while the evader and defender form an alliance to prevent the pursuer from achieving its goal.First,the behavioral modes of the pursuer,including attack and avoidance modes,were established using differential game theory.These modes are then recognized by an interactive multiple model-matching algorithm(IMM),that uses several smooth variable structure filters to match the modes of the pursuer and update their probabilities in real time.Based on the linear-quadratic optimization theory,combined with the results of strategy identification,a two-way cooperative optimal strategy for the defender and evader is proposed,where the evader aids the defender to intercept the pursuer by performing luring maneuvers.Simulation results show that the interactive multi-model algorithm based on several smooth variable structure filters perform well in the strategy identification of the pursuer,and the cooperative defense strategy based on strategy identification has good interception performance when facing pursuers,who are able to flexibly adjust their game objectives.展开更多
This paper proposes a distributed event-triggered control(ETC)framework to address cooperative target fencing challenges in UAV swarm.The proposed architecture eliminates the reliance on preset formation parameters wh...This paper proposes a distributed event-triggered control(ETC)framework to address cooperative target fencing challenges in UAV swarm.The proposed architecture eliminates the reliance on preset formation parameters while achieving multi-objective cooperative control for target fencing,network connectivity preservation,collision avoidance,and communication efficiency optimization.Firstly,a differential state observer is constructed to obtain the target's unmeasurable states.Secondly,leveraging swarm selforganization principles,a geometric-constraint-free distributed fencing controller is designed by integrating potential field methods with consensus theory.The controller dynamically adjusts inter-UAV distances via single potential function,enabling coordinated optimization of persistent network connectivity and collision-free motion during target fencing.Thirdly,a dual-threshold ETC mechanism based on velocity consensus deviation and fencing error is proposed,which can be triggered based on task features to dynamically adjust the communication frequency,significantly reduce the communication burden and exclude Zeno behavior.Theoretical analysis demonstrates the stability of closed-loop systems.Multi-scenario simulations show that the proposed method can achieve robust fencing under target maneuverability,partial UAV failures,and communication disturbances.展开更多
Signal filtering and differential acquisition are classic yet challenging issues in control engineering.The discrete-time optimal control(DTOC)based on classic tracking differentiator(TD)can effectively extract differ...Signal filtering and differential acquisition are classic yet challenging issues in control engineering.The discrete-time optimal control(DTOC)based on classic tracking differentiator(TD)can effectively extract differentiation signals and filter signals,while eliminating the chattering problem that arises during the discretization of the continuous solution.However,under external disturbance,the convergence mode may change,leading to overshoot and noise amplification.In this paper,a dual-switching strategy is proposed,which can alternate between the base double-integral system and its dual system according to the quadrant of the system’s state.And a novel linearized control law is also introduced,deriving a novel dual-switch tracking differentiator.Further analysis of system convergence and time optimality is provided.Simulation results show that the application of this dual-switching strategy notably reduces overshoot in both tracking and differential signals while enhancing noise filtering performance.Moreover,experiments conducted on a permanent magnet synchronous motor(PMSM)platform,where the proposed TD acts as a filter in the speed feedback loop,demonstrate that the standard deviation between the reference speed and the target speed(at a constant speed of 378 r/min)decreased from 5.63 r/min to 4.93 r/min,compared to the moving average algorithm.展开更多
现有电力系统稳定器(power system stabilizer,PSS)和直流调制多使用本地信号作为控制器反馈输入信号,控制器间的交互作用可能降低甚至破坏系统稳定性。提出了一种基于广域测量信号的PSS与直流调制协调策略,首先通过留数法选择对于振荡...现有电力系统稳定器(power system stabilizer,PSS)和直流调制多使用本地信号作为控制器反馈输入信号,控制器间的交互作用可能降低甚至破坏系统稳定性。提出了一种基于广域测量信号的PSS与直流调制协调策略,首先通过留数法选择对于振荡模态可观性较强的广域信号作为阻尼控制器备选反馈信号;其次通过相对增益方法选择使PSS和直流调制交互影响最小的备选信号作为最佳反馈信号;而后设计分散控制器,并运用基于混沌和差分进化的混合粒子群优化算法对PSS和直流调制控制器参数进行协调优化。最后,通过EPRI 36节点系统仿真验证了协调策略的正确性和有效性。展开更多
基金supported by the National Natural Science Foundation of China (60673142)Applied Basic Research Project of Sichuan Province (2006J13-067)
文摘To improve the resource utilization ratio and shorten the recovery time of the shared path protection with differentiated reliability （SPP-DiR） algorithm, an algorithm called dynamic shared segment protection with differentiated reliability （DSSP-DiR） is proposed for survivable GMPLS networks. In the proposed algorithm, a primary path is dynamically divided into several segments according to the differentiated reliability requirements of the customers. In the SPP-DiR algorithm, the whole primary path should be protected, while in the DSSP- DiR algorithm, only partial segments on the primary path need to be protected, which can reduce more backup bandwidths than that in the SPP-DiR algorithm. Simulation results show that the DSSP-DiR algorithm achieves higher resource utilization ratio, lower protection failure probability, and shorter recovery time than the SPP-DiR algorithm.
基金National Natural Science Foundation of China(NSFC61773142,NSFC62303136)。
文摘When the maneuverability of a pursuer is not significantly higher than that of an evader,it will be difficult to intercept the evader with only one pursuer.Therefore,this article adopts a two-to-one differential game strategy,the game of kind is generally considered to be angle-optimized,which allows unlimited turns,but these practices do not take into account the effect of acceleration,which does not correspond to the actual situation,thus,based on the angle-optimized,the acceleration optimization and the acceleration upper bound constraint are added into the game for consideration.A two-to-one differential game problem is proposed in the three-dimensional space,and an improved multi-objective grey wolf optimization(IMOGWO)algorithm is proposed to solve the optimal game point of this problem.With the equations that describe the relative motions between the pursuers and the evader in the three-dimensional space,a multi-objective function with constraints is given as the performance index to design an optimal strategy for the differential game.Then the optimal game point is solved by using the IMOGWO algorithm.It is proved based on Markov chains that with the IMOGWO,the Pareto solution set is the solution of the differential game.Finally,it is verified through simulations that the pursuers can capture the escapee,and via comparative experiments,it is shown that the IMOGWO algorithm performs well in terms of running time and memory usage.
基金supported by grants from the Liaoning Province Excellent Talent Program Project(XLYC1902031)Dalian Science and Technology Talent Innovation Plan Grant(2022RG18)Basic Research Project of the Department of Education of Liaoning Province(LJKQZ20222395)。
文摘Objective Cerebral palsy(CP)is a prevalent neurodevelopmental disorder acquired during the perinatal period,with periventricular white matter injury(PWMI)serving as its primary pathological hallmark.PWMI is characterized by the loss of oligodendrocytes(OLs)and the disintegration of myelin sheaths,leading to impaired neural connectivity and motor dysfunction.Neural stem cells(NSCs)represent a promising regenerative source for replenishing lost OLs;however,conventional twodimensional(2D)in vitro culture systems lack the three-dimensional(3D)physiological microenvironment.Microfluidic chip technology has emerged as a powerful tool to overcome this limitation by enabling precise spatial and temporal control over 3D microenvironmental conditions,including the establishment of stable concentration gradients of bioactive molecules.Catalpol,an iridoid glycoside derived from traditional medicinal plants,exhibits dual antioxidant and anti-apoptotic properties.Despite its therapeutic potential,the capacity of catalpol to drive NSC differentiation toward OLs under biomimetic 3D conditions,as well as the underlying molecular mechanisms,remains poorly understood.This study aims to develop a microfluidic-based 3D biomimetic platform to systematically investigate the concentration-dependent effects of catalpol on promoting NSCs-to-OLs differentiation and to elucidate the role of the caveolin-1(Cav-1)signaling pathway in this process.Methods We developed a novel multiplexed microfluidic device featuring parallel microchannels with integrated gradient generators capable of establishing and maintaining precise linear concentration gradients(0-3 g/L catalpol)across 3D NSCs cultures.This platform facilitated the continuous perfusion culture of NSC-derived 3D spheroids,mimicking the dynamic in vivo microenvironment.Real-time cell viability was assessed using Calcein-AM/propidium iodide(PI)dual staining,with fluorescence imaging quantifying live/dead cell ratios.Oligodendrocyte differentiation was evaluated through quantitative reverse transcription polymerase chain reaction(qRT-PCR)for MBP and SOX10 gene expression,complemented by immunofluorescence staining to visualize corresponding protein changes.To dissect the molecular mechanism,the Cav-1-specific pharmacological inhibitor methyl‑β‑cyclodextrin(MCD)was employed to perturb the pathway,and its effects on differentiation markers were analyzed.Results Catalpol demonstrated excellent biocompatibility,with cell viability exceeding 96%across the entire tested concentration range(0-3 g/L),confirming its non-cytotoxic nature.At the optimal concentration of 0-3 g/L,catalpol significantly upregulated both MBP and SOX10 expression(P<0.05,P<0.01),indicating robust promotion of oligodendroglial differentiation.Intriguingly,Cav-1 mRNA expression was progressively downregulated during NSC differentiation into OLs.Further inhibition of Cav-1 with MCD further enhanced this effect,leading to a statistically significant increase in OL-specific gene expression(P<0.05,P<0.01),suggesting Cav-1 acts as a negative regulator of OLs differentiation.Conclusion This study established an integrated microfluidic gradient chip-3D NSC spheroid culture system,which combines the advantages of precise chemical gradient control with physiologically relevant 3D cell culture.The findings demonstrate that 3 g/L catalpol effectively suppresses Cav-1 signaling to drive NSC differentiation into functional OLs.This work not only provides novel insights into the Cav-1-dependent mechanisms of myelination but also delivers a scalable technological platform for future research on remyelination therapies,with potential applications in cerebral palsy and other white matter disorders.The platform’s modular design permits adaptation for screening other neurogenic compounds or investigating additional signaling pathways involved in OLs maturation.
基金Supported by Natural Science Foundation of Guangdong Province in China(2018KTSCX161)。
文摘The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic functions in the unit ball by radial derivative.Then we extend the Sharma's results.
基金supported by the PhD Research Startup Foundation of Hubei University of Economics(Grand No.XJ23BS42).
文摘This paper studies the Smoluchowski–Kramers approximation for a discrete-time dynamical system modeled as the motion of a particle in a force field.We show that the approximation holds for the drift-implicit Euler–Maruyama discretization and derive its convergence rate.In particular,the solution of the discretized system converges to the solution of the first-order limit equation in the mean-square sense,and this convergence is independent of the order in which the mass parameterμand the step size h tend to zero.
文摘Objective:To evaluate the predictive value of the neutrophil⁃to⁃lymphocyte ratio(NLR)and the systemic immune⁃inflammation index(SII)in predicting patients with anti⁃melanoma differentiation⁃associated gene 5⁃positive(anti⁃MDA5+)dermatomyositis(DM)develop into the rapidly progressive interstitial lung disease(RPILD).Methods:We retrospectively analyzed the clinical and laboratory data of 124 anti⁃MDA5+DM patients from the First Affiliated Hospital of Nanjing Medical University between March 2019 and September 2023.We identified independent risk factors associated with the development and mortality of RPILD with the Cox regression analysis,and determined the optimal cut⁃off values for predicting adverse outcomes with the receiver operating characteristic(ROC)curve analysis.Results:Among the 124 patients,36 patients(29.03%)developed RPILD,and 39 patients(31.45%)died during the follow⁃up period.The results of multivariate Cox regression analysis showed that the elevated NLR was an independent risk factor for RPILD development,while the elevated SII expression was independently associated with the increased mortality of RPILD.Based on the ROC curve analysis,NLR>6.12 was a predictor for RPILD,and SII>875.79 was associated with increased mortality risk of RPILD.Conclusion:Both NLR and SII are accessible,cost⁃effective,and reliable prognostic indicators for the prognosis of patients with anti⁃MDA5^(+)DM,providing a valuable guidance for clinical management and risk stratification of the disease.
基金support received by the National Natural Science Foundation of China(Grant Nos.52372398&62003272).
文摘Dynamic soaring,inspired by the wind-riding flight of birds such as albatrosses,is a biomimetic technique which leverages wind fields to enhance the endurance of unmanned aerial vehicles(UAVs).Achieving a precise soaring trajectory is crucial for maximizing energy efficiency during flight.Existing nonlinear programming methods are heavily dependent on the choice of initial values which is hard to determine.Therefore,this paper introduces a deep reinforcement learning method based on a differentially flat model for dynamic soaring trajectory planning and optimization.Initially,the gliding trajectory is parameterized using Fourier basis functions,achieving a flexible trajectory representation with a minimal number of hyperparameters.Subsequently,the trajectory optimization problem is formulated as a dynamic interactive process of Markov decision-making.The hyperparameters of the trajectory are optimized using the Proximal Policy Optimization(PPO2)algorithm from deep reinforcement learning(DRL),reducing the strong reliance on initial value settings in the optimization process.Finally,a comparison between the proposed method and the nonlinear programming method reveals that the trajectory generated by the proposed approach is smoother while meeting the same performance requirements.Specifically,the proposed method achieves a 34%reduction in maximum thrust,a 39.4%decrease in maximum thrust difference,and a 33%reduction in maximum airspeed difference.
基金the Science and Technology Department,Heilongjiang Province under Grant Agreement No JJ2022LH0315。
文摘This paper presents a mode-switching collaborative defense strategy for spacecraft pursuit-evasiondefense scenarios.In these scenarios,the pursuer tries to avoid the defender while capturing the evader,while the evader and defender form an alliance to prevent the pursuer from achieving its goal.First,the behavioral modes of the pursuer,including attack and avoidance modes,were established using differential game theory.These modes are then recognized by an interactive multiple model-matching algorithm(IMM),that uses several smooth variable structure filters to match the modes of the pursuer and update their probabilities in real time.Based on the linear-quadratic optimization theory,combined with the results of strategy identification,a two-way cooperative optimal strategy for the defender and evader is proposed,where the evader aids the defender to intercept the pursuer by performing luring maneuvers.Simulation results show that the interactive multi-model algorithm based on several smooth variable structure filters perform well in the strategy identification of the pursuer,and the cooperative defense strategy based on strategy identification has good interception performance when facing pursuers,who are able to flexibly adjust their game objectives.
文摘This paper proposes a distributed event-triggered control(ETC)framework to address cooperative target fencing challenges in UAV swarm.The proposed architecture eliminates the reliance on preset formation parameters while achieving multi-objective cooperative control for target fencing,network connectivity preservation,collision avoidance,and communication efficiency optimization.Firstly,a differential state observer is constructed to obtain the target's unmeasurable states.Secondly,leveraging swarm selforganization principles,a geometric-constraint-free distributed fencing controller is designed by integrating potential field methods with consensus theory.The controller dynamically adjusts inter-UAV distances via single potential function,enabling coordinated optimization of persistent network connectivity and collision-free motion during target fencing.Thirdly,a dual-threshold ETC mechanism based on velocity consensus deviation and fencing error is proposed,which can be triggered based on task features to dynamically adjust the communication frequency,significantly reduce the communication burden and exclude Zeno behavior.Theoretical analysis demonstrates the stability of closed-loop systems.Multi-scenario simulations show that the proposed method can achieve robust fencing under target maneuverability,partial UAV failures,and communication disturbances.
基金Project(QZKFKT2023-012)supported by the State Key Laboratory of Heavy-duty and Express High-power Electric Locomotive,China。
文摘Signal filtering and differential acquisition are classic yet challenging issues in control engineering.The discrete-time optimal control(DTOC)based on classic tracking differentiator(TD)can effectively extract differentiation signals and filter signals,while eliminating the chattering problem that arises during the discretization of the continuous solution.However,under external disturbance,the convergence mode may change,leading to overshoot and noise amplification.In this paper,a dual-switching strategy is proposed,which can alternate between the base double-integral system and its dual system according to the quadrant of the system’s state.And a novel linearized control law is also introduced,deriving a novel dual-switch tracking differentiator.Further analysis of system convergence and time optimality is provided.Simulation results show that the application of this dual-switching strategy notably reduces overshoot in both tracking and differential signals while enhancing noise filtering performance.Moreover,experiments conducted on a permanent magnet synchronous motor(PMSM)platform,where the proposed TD acts as a filter in the speed feedback loop,demonstrate that the standard deviation between the reference speed and the target speed(at a constant speed of 378 r/min)decreased from 5.63 r/min to 4.93 r/min,compared to the moving average algorithm.
文摘现有电力系统稳定器(power system stabilizer,PSS)和直流调制多使用本地信号作为控制器反馈输入信号,控制器间的交互作用可能降低甚至破坏系统稳定性。提出了一种基于广域测量信号的PSS与直流调制协调策略,首先通过留数法选择对于振荡模态可观性较强的广域信号作为阻尼控制器备选反馈信号;其次通过相对增益方法选择使PSS和直流调制交互影响最小的备选信号作为最佳反馈信号;而后设计分散控制器,并运用基于混沌和差分进化的混合粒子群优化算法对PSS和直流调制控制器参数进行协调优化。最后,通过EPRI 36节点系统仿真验证了协调策略的正确性和有效性。
