Smart elastomers have attracted great interest due to their excellent adaptability to changing environments and affinity to living organisms,characterized by their ability to undergo programmable deformations or prope...Smart elastomers have attracted great interest due to their excellent adaptability to changing environments and affinity to living organisms,characterized by their ability to undergo programmable deformations or property changes in response to external stimuli(e.g.,heat,light,pH,or electric/magnetic fields).They exhibit huge potential to drive the innovation of soft actuators,robotics,biomedical devices,and wearable electronics.This special issue of Chinese Journal of Polymer Science(CJPS)is dedicated to showcasing cutting-edge advancements in liquid crystal elastomers,hydrogels and the related soft actuators,with a focus on the design,synthesis,characterization,and application of stimuli-responsive soft elastomers and their integration into functional actuation systems.展开更多
The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high effic...The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high efficiency,and they can be controlled by a low power source.Nevertheless,the most popular ionic polymers are derived from fossil-based resources.Hence,it is now deemed crucial to produce these actuators using sustainable materials.In this review,the use of ionic polymeric materials as actuators is reviewed through the emphasis on their role in the domain of renewablematerials.The reviewencompasses recent advancements inmaterial formulation and performance enhancement,alongside a comparative analysis with conventional actuator systems.It was found that renewable polymeric actuators based on ionic gels and conductive polymers are easier to prepare compared to ionic polymermetal composites.In addition,the proportion of actuator manufacturing utilizing renewable materials rose to 90%,particularly for ion gel actuators,which was related to the possibility of using renewable polymers as ionic or conductive substances.Moreover,the possible improvements in biopolymeric actuators will experience an annual rise of at least 10%over the next decade,correlating with the growth of their market,which aligns with the worldwide goal of reducing global warming.Additionally,compared to fossil-derived polymers,the decomposition rate of renewable materials reaches 100%,while biodegradable fossil-based substances can exceed 60%within several weeks.Ultimately,this review aims to elucidate the potential of ionic polymeric materials as a viable and sustainable solution for future actuator technologies.展开更多
Flexible underwater vehicles with high maneuverability,high efficiency,high speed,and low disturbance have shown great application potential and research significance in underwater engineering,ocean exploration,scient...Flexible underwater vehicles with high maneuverability,high efficiency,high speed,and low disturbance have shown great application potential and research significance in underwater engineering,ocean exploration,scientific investigation and other fields.The research and development of flexible stimulus-responsive actuators is key to the development of high-performance underwater vehicles.At present,the main drive methods for underwater devices include electric drive,magnetic drive,light drive,thermal drive,and chemical drive.In this work,the research progress of stimuli-responsive actuators in water environment is reviewed from the stimuli-responsive patterns,functional design,fabrication methods,and applications in water environment.Firstly,the actuation principles and characteristics of electro-responsive,magnetic-responsive,photo-responsive,thermo-responsive actuators,and chemically responsive actuators are reviewed.Subsequently,several design requirements for the desired flexible actuators are introduced.After that,the common fabrication methods are summarized.The typical application of the stimuli-responsive actuator in the water environment is further discussed in combination with the multi-stimuli-responsive characteristics.Finally,the challenges faced by the application of stimuli-responsive actuators in the water environment are analyzed,and the corresponding viewpoints are presented.This review offers guidance for designing and preparing stimulus-responsive actuators and outlines directions for further development in fields such as ocean energy exploration and surface reconnaissance.展开更多
Liquid crystal elastomers(LCEs)exhibit exceptional reversible deformation and unique physical properties owing to their order-disorder phase transition under external stimuli.Among these deformations,helical structure...Liquid crystal elastomers(LCEs)exhibit exceptional reversible deformation and unique physical properties owing to their order-disorder phase transition under external stimuli.Among these deformations,helical structures have attracted attention owing to their distinctive configurations and promising applications in biomimetics and microelectronics.However,the helical deformation behavior of fiber actuators is critically influenced by their morphologies and alignments;yet,the underlying mechanisms are not fully understood.Through a two-step azaMichael addition reaction and direct ink writing(DIW)4D printing technology,fiber-based LCE actuators with a core-sheath alignment structure were fabricated and exhibited reversible helical deformation upon heating.By adjusting the printing parameters,the filament number,width,thickness,and core-sheath structure of the fiber actuators can be precisely controlled,resulting in deformation behaviors,such as contraction,bending,and helical twisting.Finite element simulations were performed to investigate the deformation behaviors of the fiber actuators,providing insights into the variations in stress and strain during the shape-changing process,which can be used to explain the shape-morphing mechanism.These findings demonstrate that the precise tuning of printing parameters enables the controllable construction of LCE actuator morphology and customization of their functional properties,paving the way for advanced applications in smart fabrics,biomedical engineering,and flexible electronics.展开更多
A theoretical analysis regarding active vibration control of rotating machines with current-controlled electrodynamic actuators between machine feet and steel frame foundation and with velocity feedback of the machine...A theoretical analysis regarding active vibration control of rotating machines with current-controlled electrodynamic actuators between machine feet and steel frame foundation and with velocity feedback of the machine feet vibrations is presented.First,a generalized mathematical formulation is derived based on a state-space description which can be used for different kinds of models(1D,2D,and 3D models).It is shown that under special boundary conditions,the control parameters can be directly implemented into the stiffness and damping matrices of the system.Based on the generalized mathematical formulation,an example of a rotating machine—described by a 2D model—with journal bearings,flexible rotor,current-controlled electrodynamic actuators,steel frame foundation,and velocity feedback of the machine feet vibrations is presented where the effectiveness of the described active vibration control system is demonstrated.展开更多
Photonic fibrous soft actuators that can modulate light and produce responsive deformation would have broad technological implications in areas,ranging from smart textiles and intelligent artificial muscles to medical...Photonic fibrous soft actuators that can modulate light and produce responsive deformation would have broad technological implications in areas,ranging from smart textiles and intelligent artificial muscles to medical devices.However,creating such multifunctional soft actuators has proved tremendously challenging.Here,we report novel cholesteric liquid crystal elastomer(CLCE)based photonic fibrous soft actuators(PFSAs).CLCE can serve as chiral photonic soft active material and allow for multiresponse in shapes and colors.We leveraged a tubularmold-based processing technology to prepare fibrous CLCE actuators,and the prepared actuators exhibit the capabilities to dynamically switch structural colors and geometrical shapes by mechanical,temperature,or light stimuli.CLCE-based PFSAs demonstrate diverse functionalities,including visual weight feedback,optically driven object manipulation,and light driven locomotion.It is anticipated that our PFSAs would offer many new possibilities for developing advanced soft actuators.展开更多
This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,na...This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,namely the Internal Torsion Spring Compliant Actuator(ICA)and the External Spring Compliant Actuator(ECA),and present a comparative analysis against the previously conceived Magnet Integrated Soft Actuator(MISA)through computational and experimental results.These actuators,employing a motor-tendon system,emulate biological muscle-like forms,enhancing artificial muscle technology.Then,applications of the proposed actuators in a robotic arm inspired by the human musculoskeletal system are presented.Experiments demonstrate satisfactory power in tasks like lifting dumbbells(peak power:36 W),playing table tennis(end-effector speed:3.2 m/s),and door opening,without compromising biomimetic aesthetics.Compared to other linear stiffness serial elastic actuators(SEAs),ECA and ICA exhibit high power-to-volume(361×10^(3)W/m^(3))and power-to-mass(111.6 W/kg)ratios respectively,endorsing the biomimetic design’s promise in robotic development.展开更多
As a kind of ionic artificial muscle material,Ionic Polymer-Metal Composites(IPMCs)have the advantages of a low drive current,light weight,and significant flexibility.IPMCs are widely used in the fields of biomedicine...As a kind of ionic artificial muscle material,Ionic Polymer-Metal Composites(IPMCs)have the advantages of a low drive current,light weight,and significant flexibility.IPMCs are widely used in the fields of biomedicine,soft robots,etc.However,the displacement and blocking force of the traditional sheet-type Nafion-IPMC need to be improved,and it has the limitation of unidirectional actuation.In this paper,a new type of short side chain Aquivion material is used as the polymer in the IPMC.The cylindrical IPMC is prepared by extrusion technology to improve its actuation performance and realize multi-degree-of-freedom motion.In comparison to the traditional Nafion-IPMC,the ion exchange capacity,specific capacitance,and conductivity of Aquivion-IPMC are improved by 28%,27%,and 32%,respectively,and the displacement and blocking force are improved by 57%and 25%,respectively.The cylindrical actuators can be deflected in eight directions.This indicates that Aquivion,as a polymer membrane for IPMC,holds significant application potential.By designing a cylindrical IPMC electrode distribution,the multi-degree-of-freedom deflection of IPMC can be realized.展开更多
Soft underwater swimming robots driven by smart materials show unique advantages in ocean exploration,such as low noise,high flexibility and good environmental interaction ability.The dielectric elastomer(DE),as a new...Soft underwater swimming robots driven by smart materials show unique advantages in ocean exploration,such as low noise,high flexibility and good environmental interaction ability.The dielectric elastomer(DE),as a new kind of soft intelligent material,has the characteristics of a low elastic modulus,large deformation range,high energy density and fast response speed.DE actuator(DEA)drive systems use the deformation characteristics of dielectric materials to drive the mechanical system,which has become a research hotspot in the field of soft robots.In this paper,a tubular actuator based on DEs is designed and its performance is studied.Firstly,the structure and driving process of a DEA are described,and a tubular DEA is designed.Studying the elongation ratio of the DEA pre-stretching shows that when the axial elongation ratio is 3 times and the circumferential elongation ratio is 4 times,the maximum deformation effect can be obtained under voltage excitation.At a voltage of 6.0 k V,a single pipe section DEA achieves a bending angle of 25.9°and a driving force of 73.8 m N.Secondly,the effect of the DEA series on the bending angle and response characteristics is studied.The experimental results show that the maximum bending angle of the three joint actuators in series can reach 59.3°under6.0 k V voltage,which significantly improves the overall bending performance.In addition,the truncation frequency of the drive module after the series is increased to 0.62 Hz,showing better frequency response capability.The excellent performance of the pipe joint actuator in its bending angle,response characteristic and driving force is verified.展开更多
With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling an...With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling and mode switching analysis of EHA used in the primary flight control actuation systems of large aircraft,addressing the challenges associated with mode switching.First,we analyze the functional architecture and operational characteristics of multi-mode EHA,and sumarize the operating modes and implementation methods.Based on the EHA system architecture,we then develop a theoretical mathematical model and a simulation model.Using the simulation model,we analyze the performance of the EHA during normal operation.Finally,the performance of the EHA during mode switching under various functional switching scenarios is investigated.The results indicate that the EHA meets the performance requirements in terms of accuracy,bandwidth,and load capacity.Additionally,the hydraulic cylinder operates smoothly during the EHA mode switching,and the response time for switching between different modes is less than the specified threshold.These findings validate the system performance of multi-mode EHA,which helps to improve the reliability of EHA and the safety of aircraft flight control systems.展开更多
As a combination of fiber optics and nanotechnology,optical micro/nanofiber(MNF)is considered as an important multifunctional building block for fabricating various miniaturized photonic devices.With the rapid progres...As a combination of fiber optics and nanotechnology,optical micro/nanofiber(MNF)is considered as an important multifunctional building block for fabricating various miniaturized photonic devices.With the rapid progress in flexible optoelectronics,MNF has been emerging as a promising candidate for assembling tactile sensors and soft actuators owing to its unique optical and mechanical properties.This review discusses the advances in MNF enabled tactile sensors and soft actuators,specifically,focusing on the latest research results over the past 5 years and the applications in health monitoring,human-machine interfaces,and robotics.Future prospects and challenges in developing flexible MNF devices are also presented.展开更多
In this research work, it has been designed a bionic robot fish structure, can swim underwater. The active compact body is powered by eight sets of symmetric PVC gel actuators with a caudal fin. The robot’s 200 mm-lo...In this research work, it has been designed a bionic robot fish structure, can swim underwater. The active compact body is powered by eight sets of symmetric PVC gel actuators with a caudal fin. The robot’s 200 mm-long, fish structure design incorporates a 55.52 angle to optimize the fish dynamics movement. It’s a fast and smooth operation and can swim. The robot can swim fast and quietly by using the right positions and the appropriate actuators on PVC gel actuators. This design entails a unique architecture that enables the robot to move safely and unobtrusively at the same time, which makes it suitable equipment for different exploration and surveillance missions in the water with speed and silent operation as the foremost concern.展开更多
Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible proc...Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible processibility for various configurations.Over the past two decades,researchers have been working on developing DE materials with improved properties and exploring innovative applications of dielectric elastomer actuators(DEAs).This review article focuses on two main topics:recent material innovation of DEs and development of multilayer stacking processes for DEAs,which are important to promoting commercialization of DEs.It begins by explaining the working principle of a DEA.Then,recently developed strategies for preparing new DE materials are introduced,including reducing mechanical stiffness,increasing dielectric permittivity,suppressing viscoelasticity loss,and mitigating electromechanical instability without pre-stretching.In the next section,different multilayer stacking methods for fabricating multilayer DEAs are discussed,including conventional dry stacking,wet stacking,a novel dry stacking method,and micro-fabrication-enabled stacking techniques.This review provides a comprehensive and up-to-date overview of recent developments in high-performance DE materials and multilayer stacking methods.It highlights the progress made in the field and also discusses potential future directions for further advancements.展开更多
This study proposes an accurate dead zone compensation control method for electro-hydrostatic actuators(EHAs)under low-speed conditions.Specifically,the nonlinear dead zone characteristics under low-speed conditions a...This study proposes an accurate dead zone compensation control method for electro-hydrostatic actuators(EHAs)under low-speed conditions.Specifically,the nonlinear dead zone characteristics under low-speed conditions are summarized based on numerous EHA experiments.An adaptive compensation function(ACF)is then constructed for the dead zone.Next,this study proposes an adaptive dead zone compensation control method for EHAs by integrating the ACF with a virtual decomposition controller(VDC)based on the established EHA model.The stability of the proposed control method is also proven.Finally,the proposed control method is verified using an EHA platform.The test results show that the dead zone trajectory tracking errors of EHAs are significantly reduced when combined with the ACF.Furthermore,since most EHAs are controlled by adjusting the motor speed,the method presented in this study is simpler and easier to use than methods that employ flow compensation.展开更多
The paper investigates the practical prescribed-time fuzzy tracking control problem for a category of nonlinear system subject to time-varying actuator faults.The presence of unknown nonlinear dynamics and actuator fa...The paper investigates the practical prescribed-time fuzzy tracking control problem for a category of nonlinear system subject to time-varying actuator faults.The presence of unknown nonlinear dynamics and actuator faults makes achieving tracking control within a prescribed-time challenging.To tackle this issue,we propose a novel practical prescribed-time fuzzy tracking control strategy,which is independent of the initial state of the system and does not rely on precise modeling of the system and actuators.We apply the approximation capabilities of fuzzy logic systems to handle the unknown nonlinear functions and unidentified actuator faults in the system.The piecewise controller and adaptive law constructed based on piecewise prescribed time-varying function and backstepping technique method establish the theoretical framework of practical prescribed-time tracking control,and extend the range of prescribed-time tracking control to infinity.Regardless of the initial conditions,the proposed control strategy can guarantee that all signals remain uniformly bounded within the practical prescribed time in the presence of unknown nonlinear item and time-varying actuator faults.Simulation example is presented to demonstrate the effectiveness of the proposed control strategy.展开更多
Traveling wave piezoelectric beam actuators(TWPBAs)present an advantageous structural configuration for self-moving actuators and hold significant promise for operation in confined spaces.However,current research on T...Traveling wave piezoelectric beam actuators(TWPBAs)present an advantageous structural configuration for self-moving actuators and hold significant promise for operation in confined spaces.However,current research on TWPBAs faces several limitations,including deficient design methods of excitation and structural parameters,inadequate evaluation metrics,and lack of a quantitative relationship between these parameters and evaluation metrics.This study presents a systematic approach to determining TWPBAs'structure and excitation parameters,proposes criteria for determining the excitation parameters through an established analytical model,and introduces an effective evaluation method for TWPBAs'driving.Through the analytical model and evaluation metrics,we reveal:(1)the coupling relationship between excitation parameters and structural parameters,(2)the influence of participating mode pairs on vibration response,(3)the quantitative relationship between the evaluation metrics and excitation parameters is also revealed.These conclusions are substantiated by the results of finite element analysis,laser vibration measurements,and motion test experiments.Notably,the practical application of TWPBAs in pipeline operations underscores their potential for use in endoscopy and precision instruments.展开更多
To improve the cruise flight performance of aircraft, two new configurations of plasma actuators(grid-type and super-dense array) were investigated to reduce the turbulent skin friction drag of a low-speed airfoil. Th...To improve the cruise flight performance of aircraft, two new configurations of plasma actuators(grid-type and super-dense array) were investigated to reduce the turbulent skin friction drag of a low-speed airfoil. The induced jet characteristics of the two actuators in quiescent air were diagnosed with high-speed particle image velocimetry(PIV), and their drag reduction efficiencies were examined under different operating conditions in a wind tunnel. The results showed that the grid-type plasma actuator was capable of producing a wall-normal jet array(peak magnitude: 1.07 m/s) similar to that generated in a micro-blowing technique, while the superdense array plasma actuator created a wavy wall-parallel jet(magnitude: 0.94 m/s) due to the discrete spanwise electrostatic forces. Under a comparable electrical power consumption level,the super-dense array plasma actuator array significantly outperformed the grid-type configuration,reducing the total airfoil friction drag by approximately 22% at a free-stream velocity of 20 m/s.The magnitude of drag reduction was proportional to the dimensionless jet velocity ratio(r), and a threshold r = 0.014 existed under which little impact on airfoil drag could be discerned.展开更多
The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital...The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital environment.This is important because,globally,railway track switches are used to allow trains to change routes;they are a key part of all railway networks.However,because track switches are single points of failure and safety-critical,their inability to operate correctly can cause significant delays and concomitant costs.In order to better understand the dynamic behaviour of switches during operation,this paper has developed a full simulation twin of a complete track switch system.The approach fuses finite element for the rail bending and motion,with physics-based models of the electromechanical actuator system and the control system.Hence,it provides researchers and engineers the opportunity to explore and understand the design space around the dynamic operation of new switches and switch machines before they are built.This is useful for looking at the modification or monitoring of existing switches,and it becomes even more important when new switch concepts are being considered and evaluated.The simulation is capable of running in real time or faster meaning designs can be iterated and checked interactively.The paper describes the modelling approach,demonstrates the methodology by developing the system model for a novel“REPOINT”switch system,and evaluates the system level performance against the dynamic performance requirements for the switch.In the context of that case study,it is found that the proposed new actuation system as designed can meet(and exceed)the system performance requirements,and that the fault tolerance built into the actuation ensures continued operation after a single actuator failure.展开更多
A hybrid compensation scheme for piezoelectric ceramic actuators(PEAs)is proposed.In the hybrid compensation scheme,the input rate-dependent hysteresis characteristics of the PEAs are compensated.The feedforward contr...A hybrid compensation scheme for piezoelectric ceramic actuators(PEAs)is proposed.In the hybrid compensation scheme,the input rate-dependent hysteresis characteristics of the PEAs are compensated.The feedforward controller is a novel input rate-dependent neural network hysteresis inverse model,while the feedback controller is a proportion integration differentiation(PID)controller.In the proposed inverse model,an input ratedependent auxiliary inverse operator(RAIO)and output of the hysteresis construct the expanded input space(EIS)of the inverse model which transforms the hysteresis inverse with multi-valued mapping into single-valued mapping,and the wiping-out,rate-dependent and continuous properties of the RAIO are analyzed in theories.Based on the EIS method,a hysteresis neural network inverse model,namely the dynamic back propagation neural network(DBPNN)model,is established.Moreover,a hybrid compensation scheme for the PEAs is designed to compensate for the hysteresis.Finally,the proposed method,the conventional PID controller and the hybrid controller with the modified input rate-dependent Prandtl-Ishlinskii(MRPI)model are all applied in the experimental platform.Experimental results show that the proposed method has obvious superiorities in the performance of the system.展开更多
This paper presents an identification of a continuous-time linear aircraft model while considering control surface actuators using the maximal length sequence signal. In the identification with the actuator, the input...This paper presents an identification of a continuous-time linear aircraft model while considering control surface actuators using the maximal length sequence signal. In the identification with the actuator, the input for identification is given by the command to the actuator or the output from the actuator. In the numerical simulation of longitudinal aircraft model identification, the identification performance is improved when the bandwidth ratio for the short-period mode and the bandwidth ratio between the actuator and the short-period mode are increased. Furthermore, a few input noises bring about an improvement in the identification performance. This may be effective in the case that the performance of the actuator is not sufficiently good in practical system identification.展开更多
文摘Smart elastomers have attracted great interest due to their excellent adaptability to changing environments and affinity to living organisms,characterized by their ability to undergo programmable deformations or property changes in response to external stimuli(e.g.,heat,light,pH,or electric/magnetic fields).They exhibit huge potential to drive the innovation of soft actuators,robotics,biomedical devices,and wearable electronics.This special issue of Chinese Journal of Polymer Science(CJPS)is dedicated to showcasing cutting-edge advancements in liquid crystal elastomers,hydrogels and the related soft actuators,with a focus on the design,synthesis,characterization,and application of stimuli-responsive soft elastomers and their integration into functional actuation systems.
基金funded by the Russian Science Foundation(RSF),grantNo.24-23-00558,https://rscf.ru/en/project/24-23-00558/(accessed on 04 February 2025).
文摘The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high efficiency,and they can be controlled by a low power source.Nevertheless,the most popular ionic polymers are derived from fossil-based resources.Hence,it is now deemed crucial to produce these actuators using sustainable materials.In this review,the use of ionic polymeric materials as actuators is reviewed through the emphasis on their role in the domain of renewablematerials.The reviewencompasses recent advancements inmaterial formulation and performance enhancement,alongside a comparative analysis with conventional actuator systems.It was found that renewable polymeric actuators based on ionic gels and conductive polymers are easier to prepare compared to ionic polymermetal composites.In addition,the proportion of actuator manufacturing utilizing renewable materials rose to 90%,particularly for ion gel actuators,which was related to the possibility of using renewable polymers as ionic or conductive substances.Moreover,the possible improvements in biopolymeric actuators will experience an annual rise of at least 10%over the next decade,correlating with the growth of their market,which aligns with the worldwide goal of reducing global warming.Additionally,compared to fossil-derived polymers,the decomposition rate of renewable materials reaches 100%,while biodegradable fossil-based substances can exceed 60%within several weeks.Ultimately,this review aims to elucidate the potential of ionic polymeric materials as a viable and sustainable solution for future actuator technologies.
基金supported by the National Key Research and Development Program of China(2022YFB4703401)the Ministry of Education Joint Fund(8091B032250)the Fundamental Research Funds for the Central Universities(B240205045)。
文摘Flexible underwater vehicles with high maneuverability,high efficiency,high speed,and low disturbance have shown great application potential and research significance in underwater engineering,ocean exploration,scientific investigation and other fields.The research and development of flexible stimulus-responsive actuators is key to the development of high-performance underwater vehicles.At present,the main drive methods for underwater devices include electric drive,magnetic drive,light drive,thermal drive,and chemical drive.In this work,the research progress of stimuli-responsive actuators in water environment is reviewed from the stimuli-responsive patterns,functional design,fabrication methods,and applications in water environment.Firstly,the actuation principles and characteristics of electro-responsive,magnetic-responsive,photo-responsive,thermo-responsive actuators,and chemically responsive actuators are reviewed.Subsequently,several design requirements for the desired flexible actuators are introduced.After that,the common fabrication methods are summarized.The typical application of the stimuli-responsive actuator in the water environment is further discussed in combination with the multi-stimuli-responsive characteristics.Finally,the challenges faced by the application of stimuli-responsive actuators in the water environment are analyzed,and the corresponding viewpoints are presented.This review offers guidance for designing and preparing stimulus-responsive actuators and outlines directions for further development in fields such as ocean energy exploration and surface reconnaissance.
基金financially supported by the National Natural Science Foundation of China(Nos.52103145 and 11832007)Science&Technology Department of Sichuan Province(No.2025ZNSFSC0352)State Key Laboratory of Polymer Materials Engineering(No.sklpme-2024-1-03)。
文摘Liquid crystal elastomers(LCEs)exhibit exceptional reversible deformation and unique physical properties owing to their order-disorder phase transition under external stimuli.Among these deformations,helical structures have attracted attention owing to their distinctive configurations and promising applications in biomimetics and microelectronics.However,the helical deformation behavior of fiber actuators is critically influenced by their morphologies and alignments;yet,the underlying mechanisms are not fully understood.Through a two-step azaMichael addition reaction and direct ink writing(DIW)4D printing technology,fiber-based LCE actuators with a core-sheath alignment structure were fabricated and exhibited reversible helical deformation upon heating.By adjusting the printing parameters,the filament number,width,thickness,and core-sheath structure of the fiber actuators can be precisely controlled,resulting in deformation behaviors,such as contraction,bending,and helical twisting.Finite element simulations were performed to investigate the deformation behaviors of the fiber actuators,providing insights into the variations in stress and strain during the shape-changing process,which can be used to explain the shape-morphing mechanism.These findings demonstrate that the precise tuning of printing parameters enables the controllable construction of LCE actuator morphology and customization of their functional properties,paving the way for advanced applications in smart fabrics,biomedical engineering,and flexible electronics.
文摘A theoretical analysis regarding active vibration control of rotating machines with current-controlled electrodynamic actuators between machine feet and steel frame foundation and with velocity feedback of the machine feet vibrations is presented.First,a generalized mathematical formulation is derived based on a state-space description which can be used for different kinds of models(1D,2D,and 3D models).It is shown that under special boundary conditions,the control parameters can be directly implemented into the stiffness and damping matrices of the system.Based on the generalized mathematical formulation,an example of a rotating machine—described by a 2D model—with journal bearings,flexible rotor,current-controlled electrodynamic actuators,steel frame foundation,and velocity feedback of the machine feet vibrations is presented where the effectiveness of the described active vibration control system is demonstrated.
基金financially supported by the National Natural Science Foundation of China(Nos.52273111 and 51873197)the Natural Science Foundation of Zhejiang Province of China(No.LR22E030004)the Foundation of Westlake University。
文摘Photonic fibrous soft actuators that can modulate light and produce responsive deformation would have broad technological implications in areas,ranging from smart textiles and intelligent artificial muscles to medical devices.However,creating such multifunctional soft actuators has proved tremendously challenging.Here,we report novel cholesteric liquid crystal elastomer(CLCE)based photonic fibrous soft actuators(PFSAs).CLCE can serve as chiral photonic soft active material and allow for multiresponse in shapes and colors.We leveraged a tubularmold-based processing technology to prepare fibrous CLCE actuators,and the prepared actuators exhibit the capabilities to dynamically switch structural colors and geometrical shapes by mechanical,temperature,or light stimuli.CLCE-based PFSAs demonstrate diverse functionalities,including visual weight feedback,optically driven object manipulation,and light driven locomotion.It is anticipated that our PFSAs would offer many new possibilities for developing advanced soft actuators.
基金research project funded by the National Natural Science Foundation of China(NSFC)under Grant 91948302 and Grant 52021003Research England fund at NERIC.
文摘This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,namely the Internal Torsion Spring Compliant Actuator(ICA)and the External Spring Compliant Actuator(ECA),and present a comparative analysis against the previously conceived Magnet Integrated Soft Actuator(MISA)through computational and experimental results.These actuators,employing a motor-tendon system,emulate biological muscle-like forms,enhancing artificial muscle technology.Then,applications of the proposed actuators in a robotic arm inspired by the human musculoskeletal system are presented.Experiments demonstrate satisfactory power in tasks like lifting dumbbells(peak power:36 W),playing table tennis(end-effector speed:3.2 m/s),and door opening,without compromising biomimetic aesthetics.Compared to other linear stiffness serial elastic actuators(SEAs),ECA and ICA exhibit high power-to-volume(361×10^(3)W/m^(3))and power-to-mass(111.6 W/kg)ratios respectively,endorsing the biomimetic design’s promise in robotic development.
基金financial support from the National Natural Science Foundation of China(Grant No.U1637101)The Research Fund of State Key Laboratory of Mechanics and Control for Aerospace Structures(1005-ZAG23011).
文摘As a kind of ionic artificial muscle material,Ionic Polymer-Metal Composites(IPMCs)have the advantages of a low drive current,light weight,and significant flexibility.IPMCs are widely used in the fields of biomedicine,soft robots,etc.However,the displacement and blocking force of the traditional sheet-type Nafion-IPMC need to be improved,and it has the limitation of unidirectional actuation.In this paper,a new type of short side chain Aquivion material is used as the polymer in the IPMC.The cylindrical IPMC is prepared by extrusion technology to improve its actuation performance and realize multi-degree-of-freedom motion.In comparison to the traditional Nafion-IPMC,the ion exchange capacity,specific capacitance,and conductivity of Aquivion-IPMC are improved by 28%,27%,and 32%,respectively,and the displacement and blocking force are improved by 57%and 25%,respectively.The cylindrical actuators can be deflected in eight directions.This indicates that Aquivion,as a polymer membrane for IPMC,holds significant application potential.By designing a cylindrical IPMC electrode distribution,the multi-degree-of-freedom deflection of IPMC can be realized.
基金Project supported by the Science and Technology Research Project of Henan Province in China(Grant No.222102220022)。
文摘Soft underwater swimming robots driven by smart materials show unique advantages in ocean exploration,such as low noise,high flexibility and good environmental interaction ability.The dielectric elastomer(DE),as a new kind of soft intelligent material,has the characteristics of a low elastic modulus,large deformation range,high energy density and fast response speed.DE actuator(DEA)drive systems use the deformation characteristics of dielectric materials to drive the mechanical system,which has become a research hotspot in the field of soft robots.In this paper,a tubular actuator based on DEs is designed and its performance is studied.Firstly,the structure and driving process of a DEA are described,and a tubular DEA is designed.Studying the elongation ratio of the DEA pre-stretching shows that when the axial elongation ratio is 3 times and the circumferential elongation ratio is 4 times,the maximum deformation effect can be obtained under voltage excitation.At a voltage of 6.0 k V,a single pipe section DEA achieves a bending angle of 25.9°and a driving force of 73.8 m N.Secondly,the effect of the DEA series on the bending angle and response characteristics is studied.The experimental results show that the maximum bending angle of the three joint actuators in series can reach 59.3°under6.0 k V voltage,which significantly improves the overall bending performance.In addition,the truncation frequency of the drive module after the series is increased to 0.62 Hz,showing better frequency response capability.The excellent performance of the pipe joint actuator in its bending angle,response characteristic and driving force is verified.
基金supported by the Chinese Civil Aircraft Project(No.MJ-2017-S49).
文摘With the advancement of more electric aircraft(MEA)technology,the application of electro-hydrostatic actuators(EHAs)in aircraft actuation systems has become increasingly prevalent.This paper focuses on the modeling and mode switching analysis of EHA used in the primary flight control actuation systems of large aircraft,addressing the challenges associated with mode switching.First,we analyze the functional architecture and operational characteristics of multi-mode EHA,and sumarize the operating modes and implementation methods.Based on the EHA system architecture,we then develop a theoretical mathematical model and a simulation model.Using the simulation model,we analyze the performance of the EHA during normal operation.Finally,the performance of the EHA during mode switching under various functional switching scenarios is investigated.The results indicate that the EHA meets the performance requirements in terms of accuracy,bandwidth,and load capacity.Additionally,the hydraulic cylinder operates smoothly during the EHA mode switching,and the response time for switching between different modes is less than the specified threshold.These findings validate the system performance of multi-mode EHA,which helps to improve the reliability of EHA and the safety of aircraft flight control systems.
基金financial supports from the National Natural Science Foundation of China(No.61975173)the Key Research and Development Project of Zhejiang Province(No.2022C03103,2023C01045).
文摘As a combination of fiber optics and nanotechnology,optical micro/nanofiber(MNF)is considered as an important multifunctional building block for fabricating various miniaturized photonic devices.With the rapid progress in flexible optoelectronics,MNF has been emerging as a promising candidate for assembling tactile sensors and soft actuators owing to its unique optical and mechanical properties.This review discusses the advances in MNF enabled tactile sensors and soft actuators,specifically,focusing on the latest research results over the past 5 years and the applications in health monitoring,human-machine interfaces,and robotics.Future prospects and challenges in developing flexible MNF devices are also presented.
文摘In this research work, it has been designed a bionic robot fish structure, can swim underwater. The active compact body is powered by eight sets of symmetric PVC gel actuators with a caudal fin. The robot’s 200 mm-long, fish structure design incorporates a 55.52 angle to optimize the fish dynamics movement. It’s a fast and smooth operation and can swim. The robot can swim fast and quietly by using the right positions and the appropriate actuators on PVC gel actuators. This design entails a unique architecture that enables the robot to move safely and unobtrusively at the same time, which makes it suitable equipment for different exploration and surveillance missions in the water with speed and silent operation as the foremost concern.
基金This work is supported by the National Natural Science Foundation of China(No.T229722).
文摘Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible processibility for various configurations.Over the past two decades,researchers have been working on developing DE materials with improved properties and exploring innovative applications of dielectric elastomer actuators(DEAs).This review article focuses on two main topics:recent material innovation of DEs and development of multilayer stacking processes for DEAs,which are important to promoting commercialization of DEs.It begins by explaining the working principle of a DEA.Then,recently developed strategies for preparing new DE materials are introduced,including reducing mechanical stiffness,increasing dielectric permittivity,suppressing viscoelasticity loss,and mitigating electromechanical instability without pre-stretching.In the next section,different multilayer stacking methods for fabricating multilayer DEAs are discussed,including conventional dry stacking,wet stacking,a novel dry stacking method,and micro-fabrication-enabled stacking techniques.This review provides a comprehensive and up-to-date overview of recent developments in high-performance DE materials and multilayer stacking methods.It highlights the progress made in the field and also discusses potential future directions for further advancements.
基金Supported by National Natural Science Foundation of China(Grant Nos.51890883,U2141209)1912 Project Foundation。
文摘This study proposes an accurate dead zone compensation control method for electro-hydrostatic actuators(EHAs)under low-speed conditions.Specifically,the nonlinear dead zone characteristics under low-speed conditions are summarized based on numerous EHA experiments.An adaptive compensation function(ACF)is then constructed for the dead zone.Next,this study proposes an adaptive dead zone compensation control method for EHAs by integrating the ACF with a virtual decomposition controller(VDC)based on the established EHA model.The stability of the proposed control method is also proven.Finally,the proposed control method is verified using an EHA platform.The test results show that the dead zone trajectory tracking errors of EHAs are significantly reduced when combined with the ACF.Furthermore,since most EHAs are controlled by adjusting the motor speed,the method presented in this study is simpler and easier to use than methods that employ flow compensation.
基金partially supported by the National Natural Science Foundation of China(62322307)Sichuan Science and Technology Program,China(2023NSFSC1968).
文摘The paper investigates the practical prescribed-time fuzzy tracking control problem for a category of nonlinear system subject to time-varying actuator faults.The presence of unknown nonlinear dynamics and actuator faults makes achieving tracking control within a prescribed-time challenging.To tackle this issue,we propose a novel practical prescribed-time fuzzy tracking control strategy,which is independent of the initial state of the system and does not rely on precise modeling of the system and actuators.We apply the approximation capabilities of fuzzy logic systems to handle the unknown nonlinear functions and unidentified actuator faults in the system.The piecewise controller and adaptive law constructed based on piecewise prescribed time-varying function and backstepping technique method establish the theoretical framework of practical prescribed-time tracking control,and extend the range of prescribed-time tracking control to infinity.Regardless of the initial conditions,the proposed control strategy can guarantee that all signals remain uniformly bounded within the practical prescribed time in the presence of unknown nonlinear item and time-varying actuator faults.Simulation example is presented to demonstrate the effectiveness of the proposed control strategy.
基金supported by the National Natural Science Foundation of China(Grant Nos.12025201,11890681,12102007).
文摘Traveling wave piezoelectric beam actuators(TWPBAs)present an advantageous structural configuration for self-moving actuators and hold significant promise for operation in confined spaces.However,current research on TWPBAs faces several limitations,including deficient design methods of excitation and structural parameters,inadequate evaluation metrics,and lack of a quantitative relationship between these parameters and evaluation metrics.This study presents a systematic approach to determining TWPBAs'structure and excitation parameters,proposes criteria for determining the excitation parameters through an established analytical model,and introduces an effective evaluation method for TWPBAs'driving.Through the analytical model and evaluation metrics,we reveal:(1)the coupling relationship between excitation parameters and structural parameters,(2)the influence of participating mode pairs on vibration response,(3)the quantitative relationship between the evaluation metrics and excitation parameters is also revealed.These conclusions are substantiated by the results of finite element analysis,laser vibration measurements,and motion test experiments.Notably,the practical application of TWPBAs in pipeline operations underscores their potential for use in endoscopy and precision instruments.
基金supported by National Natural Science Foundation of China (Nos.12002384, U2341277,and 52025064)Foundation Strengthening Program (No.2021JJ-0786)。
文摘To improve the cruise flight performance of aircraft, two new configurations of plasma actuators(grid-type and super-dense array) were investigated to reduce the turbulent skin friction drag of a low-speed airfoil. The induced jet characteristics of the two actuators in quiescent air were diagnosed with high-speed particle image velocimetry(PIV), and their drag reduction efficiencies were examined under different operating conditions in a wind tunnel. The results showed that the grid-type plasma actuator was capable of producing a wall-normal jet array(peak magnitude: 1.07 m/s) similar to that generated in a micro-blowing technique, while the superdense array plasma actuator created a wavy wall-parallel jet(magnitude: 0.94 m/s) due to the discrete spanwise electrostatic forces. Under a comparable electrical power consumption level,the super-dense array plasma actuator array significantly outperformed the grid-type configuration,reducing the total airfoil friction drag by approximately 22% at a free-stream velocity of 20 m/s.The magnitude of drag reduction was proportional to the dimensionless jet velocity ratio(r), and a threshold r = 0.014 existed under which little impact on airfoil drag could be discerned.
基金This research was supported by the European Union’s‘Shift2Rail’through No.826255 for the project IN2TRACK2:Research into enhanced track and switch and crossing system 2
文摘The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital environment.This is important because,globally,railway track switches are used to allow trains to change routes;they are a key part of all railway networks.However,because track switches are single points of failure and safety-critical,their inability to operate correctly can cause significant delays and concomitant costs.In order to better understand the dynamic behaviour of switches during operation,this paper has developed a full simulation twin of a complete track switch system.The approach fuses finite element for the rail bending and motion,with physics-based models of the electromechanical actuator system and the control system.Hence,it provides researchers and engineers the opportunity to explore and understand the design space around the dynamic operation of new switches and switch machines before they are built.This is useful for looking at the modification or monitoring of existing switches,and it becomes even more important when new switch concepts are being considered and evaluated.The simulation is capable of running in real time or faster meaning designs can be iterated and checked interactively.The paper describes the modelling approach,demonstrates the methodology by developing the system model for a novel“REPOINT”switch system,and evaluates the system level performance against the dynamic performance requirements for the switch.In the context of that case study,it is found that the proposed new actuation system as designed can meet(and exceed)the system performance requirements,and that the fault tolerance built into the actuation ensures continued operation after a single actuator failure.
基金National Natural Science Foundation of China(Nos.62171285,61971120 and 62327807)。
文摘A hybrid compensation scheme for piezoelectric ceramic actuators(PEAs)is proposed.In the hybrid compensation scheme,the input rate-dependent hysteresis characteristics of the PEAs are compensated.The feedforward controller is a novel input rate-dependent neural network hysteresis inverse model,while the feedback controller is a proportion integration differentiation(PID)controller.In the proposed inverse model,an input ratedependent auxiliary inverse operator(RAIO)and output of the hysteresis construct the expanded input space(EIS)of the inverse model which transforms the hysteresis inverse with multi-valued mapping into single-valued mapping,and the wiping-out,rate-dependent and continuous properties of the RAIO are analyzed in theories.Based on the EIS method,a hysteresis neural network inverse model,namely the dynamic back propagation neural network(DBPNN)model,is established.Moreover,a hybrid compensation scheme for the PEAs is designed to compensate for the hysteresis.Finally,the proposed method,the conventional PID controller and the hybrid controller with the modified input rate-dependent Prandtl-Ishlinskii(MRPI)model are all applied in the experimental platform.Experimental results show that the proposed method has obvious superiorities in the performance of the system.
文摘This paper presents an identification of a continuous-time linear aircraft model while considering control surface actuators using the maximal length sequence signal. In the identification with the actuator, the input for identification is given by the command to the actuator or the output from the actuator. In the numerical simulation of longitudinal aircraft model identification, the identification performance is improved when the bandwidth ratio for the short-period mode and the bandwidth ratio between the actuator and the short-period mode are increased. Furthermore, a few input noises bring about an improvement in the identification performance. This may be effective in the case that the performance of the actuator is not sufficiently good in practical system identification.
