Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling ...Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.展开更多
The Hydro-Viscous Drive(HVD)speed regulating system finds extensive application in air transport transmission systems to regulate the stepless speed or conduct overload protection.However,its intrinsic hysteretic beha...The Hydro-Viscous Drive(HVD)speed regulating system finds extensive application in air transport transmission systems to regulate the stepless speed or conduct overload protection.However,its intrinsic hysteretic behaviors,such as the asymmetric hysteretic and dead zone,could introduce inaccuracy and delay in control applications,posing challenges to system regulation.This paper investigates a Nonlinear Hysteresis Compensation Control(NHCC)that consists of two parts to control the HVD output speed by operating the valve under different engine operating conditions.In the first part,the Inverse Hysteresis Compensator(IHC)based on major loop data is introduced for the asymmetric hysteresis characterization and compensation of the HVD speed control system of the power generation and distribution,which aims to reduce the hysteresis and dead zone effect and expand the effective input range.In the second part,the Active Disturbance Rejection Controller(ADRC)is employed to mitigate the hysteresis effects of the compensated system and remove the steady-state error,which allows real-time compensation of the estimated perturbations as state feedback to achieve the required performance.An experimental laboratory station has been fabricated to evaluate the proposed method.The test results show that the NHCC method can regulate the fan speed to the desired value(45 r/min at steady state)and broaden the effective input range to the full range under different engine conditions.Besides,the proposed control method can reduce the non-linearity of the input and output curves(from 18%to 4%)and compensate for the asymmetric hysteresis(from 38%to 5%).展开更多
An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This ...An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This paper presents a robust solution in the form of a fast flutter suppression digital control logic of edge computing aileron mechatronics(ECAM).We have effectively eliminated passive and active oscillating response biases by integrating nonlinear functional parameters and an antiphase hysteresis Schmitt trigger.Our findings demonstrate that self-tuning nonlinear parameters can optimize stability,robustness,and accuracy.At the same time,the antiphase hysteresis Schmitt trigger effectively rejects flutters without the need for collaborative navigation and guidance.Our hardware-in-the-loop simulation results confirm that this approach can eliminate aircraft jitter and shaking while ensuring expected stability and maneuverability.In conclusion,this nonlinear aileron mechatronics with a Schmitt positive feedback mechanism is a highly effective solution for distributed flight control and active flutter rejection.展开更多
Stretchable strain sensors are a crucial component in various applications,such as wearable devices,human-machine interfaces,and soft robotics.Hence,strain sensors with low hysteresis,high fidelity,and accurate sensin...Stretchable strain sensors are a crucial component in various applications,such as wearable devices,human-machine interfaces,and soft robotics.Hence,strain sensors with low hysteresis,high fidelity,and accurate sensing ability are urgently required for the precise measurement of large and high-frequency dynamic deformations.However,the existing hysteresis of the current functional materials utilized in strain sensors significantly impedes the achievement of these properties.Herein,we introduce an ultralow dynamic hysteresis capacitive strain sensor using a low-hysteresis and high-relative-permittivity ionic liquid-elastomer composite as the dielectric material.Based on the low-hysteresis dielectric,the prepared capacitive strain sensors exhibit ultralow electrical hysteresis(2.20%at a strain rate of 100% s^(-1)and strain of100%)and maintain low electrical hysteresis(4.35%)even under extremely high strain rates and large dynamic strain loads(a strain rate of 500% s^(-1)and strain of 100%).Moreover,the strain sensor manifests exceptional cyclic stability under 50,000 cycles of 100%strain at a strain rate of 200% s^(-1);the response curves remain nearly identical throughout these 50,000 cycles.Furthermore,the ultralowhysteresis strain sensor was successfully applied to accurate and reliable real-time human-machine interactions,revealing its great potential in various fields,including electronic skin,flexible robotics,wearable electronics,and virtual reality.展开更多
The increasingly stringent performance requirements of modern flight vehicles expose the possibilities of their coupled nonlinearities.Nevertheless,the aeroelastic response of a flight vehicle is generally predicted w...The increasingly stringent performance requirements of modern flight vehicles expose the possibilities of their coupled nonlinearities.Nevertheless,the aeroelastic response of a flight vehicle is generally predicted with isolated aerodynamic or structural nonlinearity.In this study,a Three-Degree-of-Freedom(3-DOF)aeroelastic model is proposed,which combines control surface hysteresis stiffness and dynamic stall aerodynamics.A control surface hysteretic model is applied to represent the nonlinear structural dynamics.The Office National d’Etudes et de Recherches Aérospatiales(ONERA)dynamic stall model is extended to a 3-DOF airfoil,considering the dynamic behavior of the control surface.The nonlinear aeroelastic model of a 3-DOF airfoil is described using a monolithic state-space equation.Henon’s event-driven scheme is used to investigate the post-flutter behavior of a 3-DOF airfoil with control surface hysteresis stiffness in a dynamic stall flow.The results indicate that the proposed model improves the numerical precision of nonlinear aerodynamic load by almost double that of the ONERA model that does not consider the dynamic behavior of the control surface.The flutter onset speed of the coupled nonlinear airfoil is overestimated by 10%using decoupled nonlinear analysis.Furthermore,the airfoil is dominated by the structural hysteresis nonlinearity and aerodynamic energy from the plunge motion at low airspeeds.As the airspeed increases,the airfoil is governed by the aerodynamic stall nonlinearity and aerodynamic energy from the pitch motion.The switch of the dominant nonlinearity induces topological changes in the aerodynamic curves,along with a threefold increase in the aerodynamic power.Excited by the increased energy,the airfoil undergoes a period-doubling bifurcation and transition to a higher-amplitude limit cycle.The theoretical results of this study are beneficial for the load design of modern flight vehicles under coupled nonlinear conditions.展开更多
Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effec...Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effective Hamiltonian method in conjuction with the phase-field model, we have successfully reproduced the thermal hysteresis observed in ferroelectric materials during phase transitions. The computational results regarding the electrocaloric effect from these two different computational scales closely align with experimental measurements. Furthermore, we analyze how the first-order ferroelectric phase transition gradually diminishes with an increasing applied electric field, exhibiting characteristics of second-order-like phase transition. By employing the characteristic parameters of thermal hysteresis, we have established a pathway for calculations across different computational scales, thereby providing theoretical support for further investigations into the properties of ferroelectric materials through concurrent multiscale simulations.展开更多
This study aims to investigate the intricate dynamic characteristics of the high-speed duct during the over-under Turbine-Based Combined Cycle(TBCC)inlet mode transition process while operating in an off-design state ...This study aims to investigate the intricate dynamic characteristics of the high-speed duct during the over-under Turbine-Based Combined Cycle(TBCC)inlet mode transition process while operating in an off-design state under throttled conditions.A typical over-under TBCC inlet,designed for a working Mach number range of 0–6 with a transition Mach number of 3.5,is examined through experimental studies in a supersonic wind tunnel with a freestream Mach number of2.9.The investigation focuses on the complex oscillatory flow and unique hysteresis observed in the mode transition process of the high-speed duct under the mildly throttled condition,utilizing highspeed schlieren and dynamic pressure acquisition system.The findings reveal that the high-speed duct undergoes four distinct oscillation stages akin to those in a higher throttled state during the mode transition,albeit with smaller dominant frequency and energy.Moreover,an irregular alternating“big/little buzz”mode is observed in the early stage of the large oscillation stage.Notably,the mildly throttled state exhibits three intriguing hysteresis properties compared to the unthrottled and higher throttled states.Firstly,hysteresis is observed in the shock train motion stage in the duct before unstart,along with the corresponding inverse process.Subsequently,hysteresis is noted in the unstart and restart of the high-speed duct,with a smaller hysteresis interval than in the unthrottled state.Finally,the hysteresis characteristics of oscillation mode switching and the corresponding inverse process are explored.Based on the analysis,the first two hysteresis phenomena are associated with the formation and dissipation of the separation bubble.The significant adverse pressure gradient constrains the cross-sectional capacity of the channel,rendering the disappearance of the separation bubble more challenging.The hysteresis in oscillation mode switching is linked to not only the channel cross-sectional capacity but also the state of the incoming boundary layer.展开更多
Purpose:The study examines the synergy and hysteresis in the evolution of funding and its supported literature,depicts their temporal correlation mechanism,which aids in improving trend predictions.Design/methodology/...Purpose:The study examines the synergy and hysteresis in the evolution of funding and its supported literature,depicts their temporal correlation mechanism,which aids in improving trend predictions.Design/methodology/approach:The study uses the LDA model to identify topics in funding texts and supported papers.A cosine similarity algorithm was employed to estimate the nexus between topics and construct the topic evolution time series.Similarly,the hysteresis effect in topic evolution is analyzed based on topic popularity and content,leading to insights into their temporal correlation mechanism.Findings:The study finds that fund and sponsored paper topics exhibit strong collaboration with a noticeable lag in evolution.The fund topics significantly influence sponsored paper topics after a two-year lag.Moreover,the lag effect is inversely proportional to the topic’s similarity.Research limitations:We use the LDA model to determine the hysteresis effect in topic evolution despite its limitations in handling long-tail words and domain-specific vocabulary.Furthermore,the timing of the emergence of the focal topic in funds is undermined,affecting the findings.Practical implications:These findings enhance the accuracy and scientific validity of trend prediction.Estimating and identifying patterns can help technology managers anticipate future research hotspots,supporting informed decision-making and technology management.Originality/value:This study introduces a research framework to quantitatively and visually analyze the hysteresis effect,revealing the correlation and evolutionary patterns between fund research topics and their funded papers.展开更多
In this study,we consider a single-link flexible manipulator in the presence of an unknown Bouc-Wen type of hysteresis and intermittent actuator faults.First,an inverse hysteresis dynamics model is introduced,and then...In this study,we consider a single-link flexible manipulator in the presence of an unknown Bouc-Wen type of hysteresis and intermittent actuator faults.First,an inverse hysteresis dynamics model is introduced,and then the control input is divided into an expected input and an error compensator.Second,a novel adaptive neural network-based control scheme is proposed to cancel the unknown input hysteresis.Subsequently,by modifying the adaptive laws and local control laws,a fault-tolerant control strategy is applied to address uncertain intermittent actuator faults in a flexible manipulator system.Through the direct Lyapunov theory,the proposed scheme allows the state errors to asymptotically converge to a specified interval.Finally,the effectiveness of the proposed scheme is verified through numerical simulations and experiments.展开更多
Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among th...Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among the input axes,and coupled linear and angular motions of the end effector.This paper presents an inverse hysteresis-coupling hybrid model to account for such hysteresis and couplings.First,a specially designed kinematic chain is adopted to transfer the pose of the end effector into the linear motions at three prismatic joints.Second,an inverse hysteresis-coupling hybrid model is developed to linearize and decouple the system via a multilayer feedforward neural network.A fractional-order PID controller is also integrated to improve the motion accuracy of the overall system.Experimental results demonstrate that the proposed method can accurately control the motion of the end effector with improved accuracy and robustness.展开更多
Poly(phthalazinone ether sulfone ketone)(PPESK)is a new-generation high-performance thermoplastic resin that exhibits excellent thermal stability and mechanical properties.However,its damage and failure mechanisms und...Poly(phthalazinone ether sulfone ketone)(PPESK)is a new-generation high-performance thermoplastic resin that exhibits excellent thermal stability and mechanical properties.However,its damage and failure mechanisms under high-temperature and high-strain-rate coupling conditions remain unclear,significantly limiting the engineering applications of PPESK-based composites in extreme environments such as aerospace.To address this issue,in this study,a temperature-controlled split Hopkinson pressure bar experimental platform was developed for dynamic tensile/compressive loading scenarios.Combined with scanning electron microscopy and molecular dynamics simulations,the thermomechanical behavior and failure mechanisms of PPESK were systematically investigated over the temperature range of 293-473 K.The study revealed a novel"dynamic hysteresis brittle behavior"and its underlying"segmental activation±response lag antagonistic mechanism".The results showed that the strain-rate-induced response lag of polymer chain segments significantly weakened the viscous dissipation capacity activated by thermal energy at elevated temperatures.Although high-strain-rate conditions led to notable enhancement in the dynamic strength of the material(with an increase of 8%-233%,reaching 130%-330%at elevated temperatures),the fracture surface morphology tended to become smoother,and brittle fracture characteristics became more pronounced.Based on these findings,a temperature±strain rate hysteresis antagonistic function was constructed,which effectively captured the competitive relationship between temperature-driven relaxation behavior and strain-rateinduced hysteresis in thermoplastic resins.A multiscale damage evolution constitutive model with temperature±rate coupling was subsequently established and numerically implemented via the VUMAT user subroutine.This study not only unveils the nonlinear damage mechanisms of PPESK under combined service temperatures and dynamic/static loading conditions,but also provides a strong theoretical foundation and engineering guidance for the constitutive modeling and parametric design of thermoplastic resin-based materials.展开更多
Polyaniline(PANi)hydrogels have a wide range of applications in artificial skin,flexible robotics,and movement monitoring.Nevertheless,limited by the modulus mismatch between rigid PANi and the soft hydrogel matrix,th...Polyaniline(PANi)hydrogels have a wide range of applications in artificial skin,flexible robotics,and movement monitoring.Nevertheless,limited by the modulus mismatch between rigid PANi and the soft hydrogel matrix,the high strength and toughness of the PANi hydrogel are mutually exclusive.Although the introduction of sacrificial bonds into the hydrogel network can alleviate this contradiction to a certain extent,it always causes pronounced energy hysteresis during hydrogel deformation.Inspired by the energy storage and release of macroscopic springs,in this work,we propose a molecular entanglement approach for the fabrication of PANi hydrogels featuring high toughness and low hysteresis,where flexible poly(ethylene glycol)(PEG)is entangled with chemically cross-linked poly(acrylic acid)(PAA)as a hydrogel matrix,and rigid PANi as a conductive filler.The resultant PAA/PEG/PANi hydrogel exhibited high mechanical properties(fracture strength of 0.75 MPa and toughness of 4.81 MJ·m^(-3))and a low energy dissipation ratio(28.2%when stretching to 300%).Moreover,the PAA/PEG/PANi hydrogel possesses a good electrical response to external forces and can be employed as a strain sensor to monitor human joint movements by producing specific electrical signals.This work provides a straightforward strategy for preparing tough conductive PANi hydrogels with low hysteresis,showing potential for the development of healthcare devices.展开更多
Piezo actuators are widely used in ultra-precision fields because of their high response and nano-scale step length.However,their hysteresis characteristics seriously affect the accuracy and stability of piezo actuato...Piezo actuators are widely used in ultra-precision fields because of their high response and nano-scale step length.However,their hysteresis characteristics seriously affect the accuracy and stability of piezo actuators.Existing methods for fitting hysteresis loops include operator class,differential equation class,and machine learning class.The modeling cost of operator class and differential equation class methods is high,the model complexity is high,and the process of machine learning,such as neural network calculation,is opaque.The physical model framework cannot be directly extracted.Therefore,the sparse identification of nonlinear dynamics(SINDy)algorithm is proposed to fit hysteresis loops.Furthermore,the SINDy algorithm is improved.While the SINDy algorithm builds an orthogonal candidate database for modeling,the sparse regression model is simplified,and the Relay operator is introduced for piecewise fitting to solve the distortion problem of the SINDy algorithm fitting singularities.The Relay-SINDy algorithm proposed in this paper is applied to fitting hysteresis loops.Good performance is obtained with the experimental results of open and closed loops.Compared with the existing methods,the modeling cost and model complexity are reduced,and the modeling accuracy of the hysteresis loop is improved.展开更多
The complex nonlinear characteristics of pneumatic soft actuators,such as asymmetric hysteresis,rate-dependence,and mechanical load-dependence,pose a challenge in accurately modeling their dynamics.To address this cha...The complex nonlinear characteristics of pneumatic soft actuators,such as asymmetric hysteresis,rate-dependence,and mechanical load-dependence,pose a challenge in accurately modeling their dynamics.To address this challenge,this paper proposes a comprehensive dynamic model aimed at describing bidirectional asymmetric hysteresis,rate-dependent,and mechanical load-dependent characteristics of a vertical pneumatic bellows actuator(PBA)system.The dynamic model contains a hysteresis submodel and a load-dependent dynamic submodel.The hysteresis submodel consists of several sets of weighted double-side play(DSP)and weighted dead-zone(DZ)operators connected in series,and it is used to model the bidirectional asymmetric hysteresis of the system.The load-dependent dynamic submodel is built based on the gated recurrent unit(GRU)neural network,and it is used to fit the nonlinear relationship between the displacement of the system and the frequency of the input air pressure as well as the mechanical load.The model parameters of the hysteresis submodel and the loaddependent dynamic submodel are determined by intelligent optimization method and neural network training method,reseparately.The fitness value(FV)between the output of the dynamic model and the experimental data is calculated to be 96.1736%,demonstrating that the parameters of the dynamic model are valid.We conduct six set of experiments to compare the model output with the experimental data,and calculate the root-meansquare errors and the maximum error,respectively.The experimental results show that,the root-mean-square error remains consistently below 2.7700%,while the maximum error remains below 8.4000%across all experiments,thereby substantiating the validity and generality of the proposed model.展开更多
This paper investigates the problem of dynamic event-triggered control for a class of large-scale nonlinear systems.In particular,both neutral delays and unknown backlash-like hysteresis are considered.This requires t...This paper investigates the problem of dynamic event-triggered control for a class of large-scale nonlinear systems.In particular,both neutral delays and unknown backlash-like hysteresis are considered.This requires to integrate a compensation mechanism into the event-triggered control architecture.To this end,dynamic gain and adaptive control techniques are introduced to address the effects of neutral delays,unknown hysteresis and parameter uncertainties simultaneously.By introducing a non-negative internal dynamic variable,a dynamic event-triggered controller is designed using the hyperbolic tangent function to reduce the communication burden.By means of the Lyapunov–Krasovskii method,it is demonstrated that all signals of the closed-loop system are globally bounded and eventually converge to a tunable bounded region.Moreover,the Zeno behavior is avoided.Finally,a simulation example is presented to verify the validity of the control scheme.展开更多
Lanthanide-based single-molecule magnets exhibit broad magnetic hysteresis,which manifests as slow magnetic relaxation in strong magnetic fields.However,the origin of the nontrivial hysteresis behaviors remains debate...Lanthanide-based single-molecule magnets exhibit broad magnetic hysteresis,which manifests as slow magnetic relaxation in strong magnetic fields.However,the origin of the nontrivial hysteresis behaviors remains debated.Here,we propose two influential mechanisms:activation of optical-phonon-mediated direct transitions within the ground-state doublet and the resonant Raman process.These discoveries,coupled with the g-factor anisotropy,account for the observed hysteresis behaviors in the regimes of fast magnetic relaxation.Our findings complement the recognized mechanisms used to interpret the magnetic hysteresis of single-molecule magnets.展开更多
A highly efficient and re liable topology-dual buck half bridge inverter (DBI) is introduced. The existenc e of discontinuous conduction mode (DCM) operation state requires the bias of in du ctor current for DBI imple...A highly efficient and re liable topology-dual buck half bridge inverter (DBI) is introduced. The existenc e of discontinuous conduction mode (DCM) operation state requires the bias of in du ctor current for DBI implemented with linear controllers like ramp comparison SP WM (RCSPWM) controllers. A novel operation scheme for DBI and a hysteresis curre nt controlled dual buck half bridge inverter (HCDBI) are proposed. The bias curr ent required by RCSPWM DBI is eliminated and conduction losses are dramatically reduced. HCDBI has greatly improved the modulation performance in DCM region for the benefit of its excellent command tracking capability. The operational schem e and control strategy are presented. Power losses of the conventional half brid ge inverter (CHBI) and HCDBI are compared with mathematical computation, and exp erimental verification is also executed. Both calculational and experimental res ults verify that HCDBI has a superior switching performance over CHBI. Its exce llent high frequency operational capacity provides another access to realize high fre quency operation of inverters.展开更多
The two-parameter Weibull model is used to describe the fiber strength distribution.The stress carried by the intact and fracture fibers on the matrix crack plane during unloading/reloading is determined based on the ...The two-parameter Weibull model is used to describe the fiber strength distribution.The stress carried by the intact and fracture fibers on the matrix crack plane during unloading/reloading is determined based on the global load sharing criterion.The axial stress distribution of intact fibers upon unloading and reloading is determined based on the mechanisms of fiber sliding relative to matrix in the interface debonded region.The interface debonded length,unloading interface counter slip length,and reloading interface new slip length are obtained by the fracture mechanics approach.The hysteresis loops corresponding to different stresses considering fiber failure are compared with the cases without considering fiber failure.The effects of fiber characteristic strength and fiber Weibull modulus on the fiber failure,the shape,and the area of the hysteresis loops are analyzed.The predicted quasi-static unloading/reloading hysteresis loops agree well with experimental data.展开更多
Observation and measurement were conducted to investigate contact angle andits hysteresis on rough surface. The experimental results indicate that the increase in solidsurface roughness enlarges advancing contact angl...Observation and measurement were conducted to investigate contact angle andits hysteresis on rough surface. The experimental results indicate that the increase in solidsurface roughness enlarges advancing contact angle and decreases receding contact angle, resultingin enhanced hysteresis. It was observed that when Young''s contact angle θ_Y 【 90°, as theroughness of solid surface increased the extent of the decrease in receding contact angle exceededthat of the increase in advancing contact angle. Based on the experimental observations, the conceptof hysteresis tension was introduced to describe the contact angle hysteresis behavior on roughsolid surface. The model provides a thoughtful understanding of the physical nature of contact anglehysteresis, in particular an instructive description of the influence of surface roughness on thehysteresis. The prediction of the model is found in quite good agreement with the experimentalobservation and measurement.展开更多
基金supported by the National Key Research and Development Program of China (MOST)(Grant No.2022YFA1402800)the Chinese Academy of Sciences (CAS) Presidents International Fellowship Initiative (PIFI)(Grant No.2025PG0006)+3 种基金the National Natural Science Foundation of China (NSFC)(Grant Nos.51831012,12274437,and 52161160334)the CAS Project for Young Scientists in Basic Research (Grant No.YSBR-084)the CAS Youth Interdisciplinary Teamthe China Postdoctoral Science Foundation (Grant No.2025M773402)。
文摘Based on the Smit-Suhl formula,we propose a universal approach for solving the magnon-magnon coupling problem in bilayer coupled systems(e.g.,antiferromagnets).This method requires only the energy expression,enabling the automatic derivation of analytical expressions for the eigenmatrix elements via symbolic computation,eliminating the need for tedious manual calculations.Using this approach,we investigate the impact of magnetic hysteresis on magnon-magnon coupling in a system with interlayer Dzyaloshinskii-Moriya interaction(DMI).The magnetic hysteresis leads to an asymmetric magnetic field dependence of the resonance frequency and alters the number of degeneracy points between the pure optical and acoustic modes.Moreover,it can result in the coupling strength at the gap of the f–H phase diagram being nearly vanishing,contrary to the conventionally expected maximum.These results deepen the understanding of the effect of interlayer DMI on magnon–magnon coupling and the proposed universal method significantly streamlines the solving process of magnon–magnon coupling problems.
文摘The Hydro-Viscous Drive(HVD)speed regulating system finds extensive application in air transport transmission systems to regulate the stepless speed or conduct overload protection.However,its intrinsic hysteretic behaviors,such as the asymmetric hysteretic and dead zone,could introduce inaccuracy and delay in control applications,posing challenges to system regulation.This paper investigates a Nonlinear Hysteresis Compensation Control(NHCC)that consists of two parts to control the HVD output speed by operating the valve under different engine operating conditions.In the first part,the Inverse Hysteresis Compensator(IHC)based on major loop data is introduced for the asymmetric hysteresis characterization and compensation of the HVD speed control system of the power generation and distribution,which aims to reduce the hysteresis and dead zone effect and expand the effective input range.In the second part,the Active Disturbance Rejection Controller(ADRC)is employed to mitigate the hysteresis effects of the compensated system and remove the steady-state error,which allows real-time compensation of the estimated perturbations as state feedback to achieve the required performance.An experimental laboratory station has been fabricated to evaluate the proposed method.The test results show that the NHCC method can regulate the fan speed to the desired value(45 r/min at steady state)and broaden the effective input range to the full range under different engine conditions.Besides,the proposed control method can reduce the non-linearity of the input and output curves(from 18%to 4%)and compensate for the asymmetric hysteresis(from 38%to 5%).
基金supported in part by the Aeronautical Science Foundation of China under Grant 2022Z005057001the Joint Research Fund of Shanghai Commercial Aircraft System Engineering Science and Technology Innovation Center under CASEF-2023-M19.
文摘An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This paper presents a robust solution in the form of a fast flutter suppression digital control logic of edge computing aileron mechatronics(ECAM).We have effectively eliminated passive and active oscillating response biases by integrating nonlinear functional parameters and an antiphase hysteresis Schmitt trigger.Our findings demonstrate that self-tuning nonlinear parameters can optimize stability,robustness,and accuracy.At the same time,the antiphase hysteresis Schmitt trigger effectively rejects flutters without the need for collaborative navigation and guidance.Our hardware-in-the-loop simulation results confirm that this approach can eliminate aircraft jitter and shaking while ensuring expected stability and maneuverability.In conclusion,this nonlinear aileron mechatronics with a Schmitt positive feedback mechanism is a highly effective solution for distributed flight control and active flutter rejection.
基金financially supported by the National Natural Science Foundation of China(Nos.52250398,52125205 and U20A20166)the Natural Science Foundation of Beijing Municipality(No.2222088)+1 种基金Shenzhen Science and Technology Program(No.KQTD20170810105439418)the Fundamental Research Funds for the Central Universities
文摘Stretchable strain sensors are a crucial component in various applications,such as wearable devices,human-machine interfaces,and soft robotics.Hence,strain sensors with low hysteresis,high fidelity,and accurate sensing ability are urgently required for the precise measurement of large and high-frequency dynamic deformations.However,the existing hysteresis of the current functional materials utilized in strain sensors significantly impedes the achievement of these properties.Herein,we introduce an ultralow dynamic hysteresis capacitive strain sensor using a low-hysteresis and high-relative-permittivity ionic liquid-elastomer composite as the dielectric material.Based on the low-hysteresis dielectric,the prepared capacitive strain sensors exhibit ultralow electrical hysteresis(2.20%at a strain rate of 100% s^(-1)and strain of100%)and maintain low electrical hysteresis(4.35%)even under extremely high strain rates and large dynamic strain loads(a strain rate of 500% s^(-1)and strain of 100%).Moreover,the strain sensor manifests exceptional cyclic stability under 50,000 cycles of 100%strain at a strain rate of 200% s^(-1);the response curves remain nearly identical throughout these 50,000 cycles.Furthermore,the ultralowhysteresis strain sensor was successfully applied to accurate and reliable real-time human-machine interactions,revealing its great potential in various fields,including electronic skin,flexible robotics,wearable electronics,and virtual reality.
文摘The increasingly stringent performance requirements of modern flight vehicles expose the possibilities of their coupled nonlinearities.Nevertheless,the aeroelastic response of a flight vehicle is generally predicted with isolated aerodynamic or structural nonlinearity.In this study,a Three-Degree-of-Freedom(3-DOF)aeroelastic model is proposed,which combines control surface hysteresis stiffness and dynamic stall aerodynamics.A control surface hysteretic model is applied to represent the nonlinear structural dynamics.The Office National d’Etudes et de Recherches Aérospatiales(ONERA)dynamic stall model is extended to a 3-DOF airfoil,considering the dynamic behavior of the control surface.The nonlinear aeroelastic model of a 3-DOF airfoil is described using a monolithic state-space equation.Henon’s event-driven scheme is used to investigate the post-flutter behavior of a 3-DOF airfoil with control surface hysteresis stiffness in a dynamic stall flow.The results indicate that the proposed model improves the numerical precision of nonlinear aerodynamic load by almost double that of the ONERA model that does not consider the dynamic behavior of the control surface.The flutter onset speed of the coupled nonlinear airfoil is overestimated by 10%using decoupled nonlinear analysis.Furthermore,the airfoil is dominated by the structural hysteresis nonlinearity and aerodynamic energy from the plunge motion at low airspeeds.As the airspeed increases,the airfoil is governed by the aerodynamic stall nonlinearity and aerodynamic energy from the pitch motion.The switch of the dominant nonlinearity induces topological changes in the aerodynamic curves,along with a threefold increase in the aerodynamic power.Excited by the increased energy,the airfoil undergoes a period-doubling bifurcation and transition to a higher-amplitude limit cycle.The theoretical results of this study are beneficial for the load design of modern flight vehicles under coupled nonlinear conditions.
基金Project supported financially by the National Natural Science Foundation of China (Grant No. 52372100)the National Key Research and Development Program of China (Grant No. 2019YFA0307900)。
文摘Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effective Hamiltonian method in conjuction with the phase-field model, we have successfully reproduced the thermal hysteresis observed in ferroelectric materials during phase transitions. The computational results regarding the electrocaloric effect from these two different computational scales closely align with experimental measurements. Furthermore, we analyze how the first-order ferroelectric phase transition gradually diminishes with an increasing applied electric field, exhibiting characteristics of second-order-like phase transition. By employing the characteristic parameters of thermal hysteresis, we have established a pathway for calculations across different computational scales, thereby providing theoretical support for further investigations into the properties of ferroelectric materials through concurrent multiscale simulations.
基金funded by the National Natural Science Foundation of China(Nos.12025202,U20A2070,12172175)the National Science and Technology Major Project,China(No.J2019-Ⅱ-0014-0035)+2 种基金the Postdoctoral Fellowship Program of CPSF,China(No.GZB20230970)the Science Center for Gas Turbine Project,China(Nos.P2022-C-II-002-001,P2022-A-II-002-001)the Young Scientific and Technological Talents Project of Jiangsu Association for Science and Technology,China(No.TJ-2021-052)。
文摘This study aims to investigate the intricate dynamic characteristics of the high-speed duct during the over-under Turbine-Based Combined Cycle(TBCC)inlet mode transition process while operating in an off-design state under throttled conditions.A typical over-under TBCC inlet,designed for a working Mach number range of 0–6 with a transition Mach number of 3.5,is examined through experimental studies in a supersonic wind tunnel with a freestream Mach number of2.9.The investigation focuses on the complex oscillatory flow and unique hysteresis observed in the mode transition process of the high-speed duct under the mildly throttled condition,utilizing highspeed schlieren and dynamic pressure acquisition system.The findings reveal that the high-speed duct undergoes four distinct oscillation stages akin to those in a higher throttled state during the mode transition,albeit with smaller dominant frequency and energy.Moreover,an irregular alternating“big/little buzz”mode is observed in the early stage of the large oscillation stage.Notably,the mildly throttled state exhibits three intriguing hysteresis properties compared to the unthrottled and higher throttled states.Firstly,hysteresis is observed in the shock train motion stage in the duct before unstart,along with the corresponding inverse process.Subsequently,hysteresis is noted in the unstart and restart of the high-speed duct,with a smaller hysteresis interval than in the unthrottled state.Finally,the hysteresis characteristics of oscillation mode switching and the corresponding inverse process are explored.Based on the analysis,the first two hysteresis phenomena are associated with the formation and dissipation of the separation bubble.The significant adverse pressure gradient constrains the cross-sectional capacity of the channel,rendering the disappearance of the separation bubble more challenging.The hysteresis in oscillation mode switching is linked to not only the channel cross-sectional capacity but also the state of the incoming boundary layer.
基金supported by National Natural Science Foundation of China(No.72104110 No.72274113)Basic Science(Natural Science)Research Projects in Higher Education Institutions in Jiangsu Province(No.22KJB630011)+2 种基金General Project of Philosophy and Social Sciences Research in Jiangsu Universities(No.2022SJYB0253)Taishan Scholar Foundation of Shandong province of China(tsqn202103069)Shandong Provincial Natural Science Foundation(No.ZR202111130115)。
文摘Purpose:The study examines the synergy and hysteresis in the evolution of funding and its supported literature,depicts their temporal correlation mechanism,which aids in improving trend predictions.Design/methodology/approach:The study uses the LDA model to identify topics in funding texts and supported papers.A cosine similarity algorithm was employed to estimate the nexus between topics and construct the topic evolution time series.Similarly,the hysteresis effect in topic evolution is analyzed based on topic popularity and content,leading to insights into their temporal correlation mechanism.Findings:The study finds that fund and sponsored paper topics exhibit strong collaboration with a noticeable lag in evolution.The fund topics significantly influence sponsored paper topics after a two-year lag.Moreover,the lag effect is inversely proportional to the topic’s similarity.Research limitations:We use the LDA model to determine the hysteresis effect in topic evolution despite its limitations in handling long-tail words and domain-specific vocabulary.Furthermore,the timing of the emergence of the focal topic in funds is undermined,affecting the findings.Practical implications:These findings enhance the accuracy and scientific validity of trend prediction.Estimating and identifying patterns can help technology managers anticipate future research hotspots,supporting informed decision-making and technology management.Originality/value:This study introduces a research framework to quantitatively and visually analyze the hysteresis effect,revealing the correlation and evolutionary patterns between fund research topics and their funded papers.
基金supported in part by the National Key Research and Development Program of China(2023YFB4706400)the National Natural Science Foundation of China(62273112,62073030,62203161)+6 种基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515120018,2023B1515120019)the Open Project of Xiangjiang Laboratory(23XJ03012)the Natural Science Foundation of Hunan Province(2024JJ5087)the Natural Science Foundation of Jiangxi Province(20232BAB212024)the National Research Foundation of Korea funded by the Ministry of Science and ICT,South Korea(IRIS-2023-00207954)the Science and Technology Planning Project of Guangzhou,China(2023A03J0120)the Guangzhou University Research Project(RC2023037)
文摘In this study,we consider a single-link flexible manipulator in the presence of an unknown Bouc-Wen type of hysteresis and intermittent actuator faults.First,an inverse hysteresis dynamics model is introduced,and then the control input is divided into an expected input and an error compensator.Second,a novel adaptive neural network-based control scheme is proposed to cancel the unknown input hysteresis.Subsequently,by modifying the adaptive laws and local control laws,a fault-tolerant control strategy is applied to address uncertain intermittent actuator faults in a flexible manipulator system.Through the direct Lyapunov theory,the proposed scheme allows the state errors to asymptotically converge to a specified interval.Finally,the effectiveness of the proposed scheme is verified through numerical simulations and experiments.
基金supported in part by the Open Fund of State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment,Guangdong University of Technology(Grant No.JMDZ2021007)in part by the Guangdong International Cooperation Program of Science and Technology(Grant No.2022A0505050078).
文摘Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among the input axes,and coupled linear and angular motions of the end effector.This paper presents an inverse hysteresis-coupling hybrid model to account for such hysteresis and couplings.First,a specially designed kinematic chain is adopted to transfer the pose of the end effector into the linear motions at three prismatic joints.Second,an inverse hysteresis-coupling hybrid model is developed to linearize and decouple the system via a multilayer feedforward neural network.A fractional-order PID controller is also integrated to improve the motion accuracy of the overall system.Experimental results demonstrate that the proposed method can accurately control the motion of the end effector with improved accuracy and robustness.
基金supported by National Key Research and Development Program"Advanced Structures and Composite Materials"Special Project[Grant No.2024YFB3712800]the Fundamental Research Funds for the Central Universities[Grant No.DUT22-LAB605]Liaoning Province's"Unveiling the List and Leading the Way"Science and Technology Research and Development Special Project[Grant No.2022JH1/10400043]。
文摘Poly(phthalazinone ether sulfone ketone)(PPESK)is a new-generation high-performance thermoplastic resin that exhibits excellent thermal stability and mechanical properties.However,its damage and failure mechanisms under high-temperature and high-strain-rate coupling conditions remain unclear,significantly limiting the engineering applications of PPESK-based composites in extreme environments such as aerospace.To address this issue,in this study,a temperature-controlled split Hopkinson pressure bar experimental platform was developed for dynamic tensile/compressive loading scenarios.Combined with scanning electron microscopy and molecular dynamics simulations,the thermomechanical behavior and failure mechanisms of PPESK were systematically investigated over the temperature range of 293-473 K.The study revealed a novel"dynamic hysteresis brittle behavior"and its underlying"segmental activation±response lag antagonistic mechanism".The results showed that the strain-rate-induced response lag of polymer chain segments significantly weakened the viscous dissipation capacity activated by thermal energy at elevated temperatures.Although high-strain-rate conditions led to notable enhancement in the dynamic strength of the material(with an increase of 8%-233%,reaching 130%-330%at elevated temperatures),the fracture surface morphology tended to become smoother,and brittle fracture characteristics became more pronounced.Based on these findings,a temperature±strain rate hysteresis antagonistic function was constructed,which effectively captured the competitive relationship between temperature-driven relaxation behavior and strain-rateinduced hysteresis in thermoplastic resins.A multiscale damage evolution constitutive model with temperature±rate coupling was subsequently established and numerically implemented via the VUMAT user subroutine.This study not only unveils the nonlinear damage mechanisms of PPESK under combined service temperatures and dynamic/static loading conditions,but also provides a strong theoretical foundation and engineering guidance for the constitutive modeling and parametric design of thermoplastic resin-based materials.
基金financially supported by the Beijing Natural Science Foundation(No.L233016)。
文摘Polyaniline(PANi)hydrogels have a wide range of applications in artificial skin,flexible robotics,and movement monitoring.Nevertheless,limited by the modulus mismatch between rigid PANi and the soft hydrogel matrix,the high strength and toughness of the PANi hydrogel are mutually exclusive.Although the introduction of sacrificial bonds into the hydrogel network can alleviate this contradiction to a certain extent,it always causes pronounced energy hysteresis during hydrogel deformation.Inspired by the energy storage and release of macroscopic springs,in this work,we propose a molecular entanglement approach for the fabrication of PANi hydrogels featuring high toughness and low hysteresis,where flexible poly(ethylene glycol)(PEG)is entangled with chemically cross-linked poly(acrylic acid)(PAA)as a hydrogel matrix,and rigid PANi as a conductive filler.The resultant PAA/PEG/PANi hydrogel exhibited high mechanical properties(fracture strength of 0.75 MPa and toughness of 4.81 MJ·m^(-3))and a low energy dissipation ratio(28.2%when stretching to 300%).Moreover,the PAA/PEG/PANi hydrogel possesses a good electrical response to external forces and can be employed as a strain sensor to monitor human joint movements by producing specific electrical signals.This work provides a straightforward strategy for preparing tough conductive PANi hydrogels with low hysteresis,showing potential for the development of healthcare devices.
基金National Natural Science Foundation of China(62203118)。
文摘Piezo actuators are widely used in ultra-precision fields because of their high response and nano-scale step length.However,their hysteresis characteristics seriously affect the accuracy and stability of piezo actuators.Existing methods for fitting hysteresis loops include operator class,differential equation class,and machine learning class.The modeling cost of operator class and differential equation class methods is high,the model complexity is high,and the process of machine learning,such as neural network calculation,is opaque.The physical model framework cannot be directly extracted.Therefore,the sparse identification of nonlinear dynamics(SINDy)algorithm is proposed to fit hysteresis loops.Furthermore,the SINDy algorithm is improved.While the SINDy algorithm builds an orthogonal candidate database for modeling,the sparse regression model is simplified,and the Relay operator is introduced for piecewise fitting to solve the distortion problem of the SINDy algorithm fitting singularities.The Relay-SINDy algorithm proposed in this paper is applied to fitting hysteresis loops.Good performance is obtained with the experimental results of open and closed loops.Compared with the existing methods,the modeling cost and model complexity are reduced,and the modeling accuracy of the hysteresis loop is improved.
基金supported in part by the Young Scientists Fund of National Natural Science Foundation of China(62203408)the Hubei Provincial Natural Science Foundation of China(2015CFA010)+1 种基金the 111 Project(B17040)China Scholarship Council(202206410070).
文摘The complex nonlinear characteristics of pneumatic soft actuators,such as asymmetric hysteresis,rate-dependence,and mechanical load-dependence,pose a challenge in accurately modeling their dynamics.To address this challenge,this paper proposes a comprehensive dynamic model aimed at describing bidirectional asymmetric hysteresis,rate-dependent,and mechanical load-dependent characteristics of a vertical pneumatic bellows actuator(PBA)system.The dynamic model contains a hysteresis submodel and a load-dependent dynamic submodel.The hysteresis submodel consists of several sets of weighted double-side play(DSP)and weighted dead-zone(DZ)operators connected in series,and it is used to model the bidirectional asymmetric hysteresis of the system.The load-dependent dynamic submodel is built based on the gated recurrent unit(GRU)neural network,and it is used to fit the nonlinear relationship between the displacement of the system and the frequency of the input air pressure as well as the mechanical load.The model parameters of the hysteresis submodel and the loaddependent dynamic submodel are determined by intelligent optimization method and neural network training method,reseparately.The fitness value(FV)between the output of the dynamic model and the experimental data is calculated to be 96.1736%,demonstrating that the parameters of the dynamic model are valid.We conduct six set of experiments to compare the model output with the experimental data,and calculate the root-meansquare errors and the maximum error,respectively.The experimental results show that,the root-mean-square error remains consistently below 2.7700%,while the maximum error remains below 8.4000%across all experiments,thereby substantiating the validity and generality of the proposed model.
基金supported by the National Natural Science Foundation of China under Grant 62073190the Science Center Program of National Natural Science Foundation of China under Grant 62188101.
文摘This paper investigates the problem of dynamic event-triggered control for a class of large-scale nonlinear systems.In particular,both neutral delays and unknown backlash-like hysteresis are considered.This requires to integrate a compensation mechanism into the event-triggered control architecture.To this end,dynamic gain and adaptive control techniques are introduced to address the effects of neutral delays,unknown hysteresis and parameter uncertainties simultaneously.By introducing a non-negative internal dynamic variable,a dynamic event-triggered controller is designed using the hyperbolic tangent function to reduce the communication burden.By means of the Lyapunov–Krasovskii method,it is demonstrated that all signals of the closed-loop system are globally bounded and eventually converge to a tunable bounded region.Moreover,the Zeno behavior is avoided.Finally,a simulation example is presented to verify the validity of the control scheme.
基金the support from the Sichuan Normal Universitysupport from the National Natural Science Foundation of China(Grant No.22375157)+1 种基金support from the National Natural Science Foundation of China(Grant Nos.12474122,52171188,51771127,and 52111530143)the Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province(Grant No.2021ZYD0025)。
文摘Lanthanide-based single-molecule magnets exhibit broad magnetic hysteresis,which manifests as slow magnetic relaxation in strong magnetic fields.However,the origin of the nontrivial hysteresis behaviors remains debated.Here,we propose two influential mechanisms:activation of optical-phonon-mediated direct transitions within the ground-state doublet and the resonant Raman process.These discoveries,coupled with the g-factor anisotropy,account for the observed hysteresis behaviors in the regimes of fast magnetic relaxation.Our findings complement the recognized mechanisms used to interpret the magnetic hysteresis of single-molecule magnets.
文摘A highly efficient and re liable topology-dual buck half bridge inverter (DBI) is introduced. The existenc e of discontinuous conduction mode (DCM) operation state requires the bias of in du ctor current for DBI implemented with linear controllers like ramp comparison SP WM (RCSPWM) controllers. A novel operation scheme for DBI and a hysteresis curre nt controlled dual buck half bridge inverter (HCDBI) are proposed. The bias curr ent required by RCSPWM DBI is eliminated and conduction losses are dramatically reduced. HCDBI has greatly improved the modulation performance in DCM region for the benefit of its excellent command tracking capability. The operational schem e and control strategy are presented. Power losses of the conventional half brid ge inverter (CHBI) and HCDBI are compared with mathematical computation, and exp erimental verification is also executed. Both calculational and experimental res ults verify that HCDBI has a superior switching performance over CHBI. Its exce llent high frequency operational capacity provides another access to realize high fre quency operation of inverters.
基金Supported by the National Natural Science Foundation of China(51075204)the Graduate Innovation Foundation of Jiangsu Province(CX08B-133Z)the Doctoral Innovation Foundation of Nanjing University of Aeronautics and Astronautics(BCXJ08-05)~~
文摘The two-parameter Weibull model is used to describe the fiber strength distribution.The stress carried by the intact and fracture fibers on the matrix crack plane during unloading/reloading is determined based on the global load sharing criterion.The axial stress distribution of intact fibers upon unloading and reloading is determined based on the mechanisms of fiber sliding relative to matrix in the interface debonded region.The interface debonded length,unloading interface counter slip length,and reloading interface new slip length are obtained by the fracture mechanics approach.The hysteresis loops corresponding to different stresses considering fiber failure are compared with the cases without considering fiber failure.The effects of fiber characteristic strength and fiber Weibull modulus on the fiber failure,the shape,and the area of the hysteresis loops are analyzed.The predicted quasi-static unloading/reloading hysteresis loops agree well with experimental data.
基金supported by the High Technology Research and Development Program of Jilin(20130204021GX)the Specialized Research Fund for Graduate Course Identification System Program(Jilin University)of China(450060523183)+2 种基金the National Natural Science Foundation of China(61520106008,U1564207,61503149)the Education Department of Jilin Province of China(2016430)the Graduate Innovation Fund of Jilin University(2016030)
文摘Observation and measurement were conducted to investigate contact angle andits hysteresis on rough surface. The experimental results indicate that the increase in solidsurface roughness enlarges advancing contact angle and decreases receding contact angle, resultingin enhanced hysteresis. It was observed that when Young''s contact angle θ_Y 【 90°, as theroughness of solid surface increased the extent of the decrease in receding contact angle exceededthat of the increase in advancing contact angle. Based on the experimental observations, the conceptof hysteresis tension was introduced to describe the contact angle hysteresis behavior on roughsolid surface. The model provides a thoughtful understanding of the physical nature of contact anglehysteresis, in particular an instructive description of the influence of surface roughness on thehysteresis. The prediction of the model is found in quite good agreement with the experimentalobservation and measurement.
