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
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 electro-hydrostatic actuator （EHA） is a kind of power-by-wire （PBW） actuator that converts the electrical power into localized hydraulic power for flight control. By removing the central hydraulic power supply...The electro-hydrostatic actuator （EHA） is a kind of power-by-wire （PBW） actuator that converts the electrical power into localized hydraulic power for flight control. By removing the central hydraulic power supply together with hydraulic pipes, an EHA＇s reliability and efficiency are greatly improved but its frequency width and stiffness decreased. To overcome the drawback, this article proposes a novel structure of EHA associated with a power regulator. Composed of a high-pressure accumulator and a proportional valve, it can store and harness the hydraulic power flexibly according to the changing control requirements. The concept of transferred volume is put forward to estimate the capability of the power regulator. The actuator output position can be kept fixed with a hydraulic lock. The compounded control is specially developed to ensure the actuator system to operate in a correct manner. The simulation results indicate that the new-brand actuator results in efficient expanding of the system frequency width with an optimal power supply.展开更多
This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/s...This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under highspeed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded.展开更多
The integrated electro-hydrostatic actuator （EHA） with variable displacement and variable rotation speed is researched. In the system, the output of the actuator is changed by controlling the rotationspeed of the br...The integrated electro-hydrostatic actuator （EHA） with variable displacement and variable rotation speed is researched. In the system, the output of the actuator is changed by controlling the rotationspeed of the brushless DC servomotor and the displacement of the servopump. The mathematical model described in state-space model is created. The system characteristics are studied based on the point of multiplicative dual-variable. And the basic method of control of the system is presented.展开更多
The electro-hydrostatic actuator(EHA)used in more electric aircraft(MEA)has been extensively studied due to its advantages of high reliability and high integration.However,this high integration results in a small heat...The electro-hydrostatic actuator(EHA)used in more electric aircraft(MEA)has been extensively studied due to its advantages of high reliability and high integration.However,this high integration results in a small heat dissipation area,leading to high-temperature problems.Generally,to reduce the temperature,a wet cooling method of using the pump leakage oil to cool the motor is adopted,which can also increase the difficulty of accurately predicting the system temperature in the early design stage.To solve this problem,a dynamic coupling thermal model of a wet EHA is proposed in this paper.In particular,the leakage oil of the pump is used as a coupling item between the electrical system and the hydraulic system.Then,an improved T-equivalent block model is proposed to address the uneven distribution of axial oil temperature inside the motor,and the control node method is applied to hydraulic system thermal modeling.Meanwhile,a dynamic coupling thermal model is developed that enables a dynamic evaluation of the wet EHA temperature.Then,experimental prototypes of wet motor and wet EHA are developed,while the temperature response of the wet motor at different rotation speeds and different loads and the temperature response of the wet EHA at no-load condition were verified experimentally at room temperature,respectively.The maximum temperature difference between the experimental and theoretical results of the wet motor as well as the experimental and theoretical results of the wet EHA is less than 8℃.These test results indicate that the dynamic coupling thermal model is valid and demonstrate that the thermal coupling modeling method proposed in this paper can provide a basis for the detailed thermal design of EHA.展开更多
The speed of an Electro-Hydrostatic Actuator(EHA) pump can recently reach 20000 r/min, and its churning losses increase obviously with an increasing speed, which results in low efficiency and thus increasing heat in a...The speed of an Electro-Hydrostatic Actuator(EHA) pump can recently reach 20000 r/min, and its churning losses increase obviously with an increasing speed, which results in low efficiency and thus increasing heat in aircraft EHA systems. In order to reduce churning losses at high speeds, more attention should be given to the design of an insert. In this paper, the effect of an insert with different design parameters on churning losses is investigated through Computational Fluid Dynamics(CFD) simulation and experiments by calculating the difference between churning losses torques of the test pump with and without the insert based on a high-speed churning losses test rig.Analytical results show that the gap between the insert and the cylinder is critical for churning losses reduction. It is found that the churning losses of the test pump can be reduced with a decreasing gap between the cylinder block and the insert at high speeds. This is because the insert can decrease the turbulence occurrence at high speeds. The results can be used for flow field analysis and optimization of the high-speed EHA pump and provide a new method for improving efficiency of high-speed EHA pumps.展开更多
The variable pump displacement and variable motor speed electro-hydrostatic actuator(EHA),one of the three types of EHAs,has advantages such as short response time,flexible speed regulation,and high efficiency.However...The variable pump displacement and variable motor speed electro-hydrostatic actuator(EHA),one of the three types of EHAs,has advantages such as short response time,flexible speed regulation,and high efficiency.However,the nonlinearity of its double-input single-output system poses a great challenge for system control.This study proposes a novel EHA with adaptive pump displacement and variable motor speed(EHA-APVM).A closed-loop position is realized using a servomotor.Moreover,the displacement varies with the system pressure;thus,the EHA-APVM is a single-input and single-output system.Firstly,the working principles of the EHA-APVM and the pump used in the system are introduced.Secondly,a nonlinear mathematical model of the proposed EHA-APVM control system is established,and a feedback back-stepping(FBBS)control algorithm is introduced to transform the complex nonlinear system into a linear system on the basis of the back-stepping control theory.Finally,simulation results prove that the EHA-APVM has a quick response and high robustness to variations of the load and the pump displacement.In this work,the size and weight of the motor are significantly reduced because the maximum power requirement is reduced,which is very beneficial for using the actuator in airborne equipment.展开更多
To improve the power density and simplify the seal structure,the Wet-Type Permanent Magnet Synchronous Motor(WTPMSM)technique has been applied to aerospace Electro-Hydrostatic Actuators(EHA).In a WTPMSM,the stator and...To improve the power density and simplify the seal structure,the Wet-Type Permanent Magnet Synchronous Motor(WTPMSM)technique has been applied to aerospace Electro-Hydrostatic Actuators(EHA).In a WTPMSM,the stator and the rotor are both immersed in the aviation hydraulic oil.Although the heat dissipation performance of the WTPMSM can be enhanced,the aviation hydraulic oil will cost an extra oil frictional loss in the narrow airgap of the WTPMSM.This paper proposes an accurate oil frictional loss model for the WTPMSM,in which the wide speed range(0–20 kr/min)and the narrowness of the airgap(0.5–1.5 mm)are its features.Firstly,the mechanism of the oil frictional loss in the airgap of the WTPMSM is revealed.Then an accurate oil frictional loss model is proposed considering the nonlinear influence caused by the Taylor vortex.Furthermore,the influence of motor dimensions on oil frictional loss is analyzed.Finally,the proposed oil frictional loss model is verified by experiments,which provides a guideline for engineers to follow in the WTPMSM design.展开更多
The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator（LEHA）. Rather than the traditional statistical methods based on degradation d...The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator（LEHA）. Rather than the traditional statistical methods based on degradation data, the method proposed in this paper firstly analyzes the dominant progressive failure mode of the LEHA based on the working principle and working conditions of the LEHA. The Computational Fluid Dynamics（CFD） method, combining the turbulent theory and the micro erosion principle, is used to establish an erosion model of the rectification mechanism. The erosion rates for different port openings, under a time-varying flow field, are obtained. The piecewise linearization method is applied to update the concentration of contaminated particles within the LEHA, in order to gain insight into the erosion degradation process at various stages of degradation. The main contribution of the proposed model is the application of the dynamic concentration of contamination particles in erosion analysis of Electro-Hydraulic Servo Valves（EHSVs）, throttle valves, spool valves, and needle valves. The effects of system parameters and working conditions on component wear are analyzed by simulations. The results of the proposed model match the expected degradation process.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
Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control....Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control.Modern chassis-by-wire systems manage an increasing number of heterogeneous chassis execution systems,including distributed drive,all-wheel drive(AWD),brake-by-wire(BBW),steer-by-wire(SBW),rear-wheel steering(RWS),active stabilizer bar(ASB)and active suspension system(ASS),greatly enhancing the controllable degrees of freedom compared to conventional chassis configurations.To advance research in chassis domain control,it is essential to understand how these heterogeneous execution systems influence vehicle dynamics.This paper focuses on the modeling and analysis of the lateral,longitudinal,and vertical chassis control and execution systems,-as well as their impact on vehicle lateral motion.Using a vehicle simulation platform,both the vehicle dynamics model and the individual dynamics models of each execution system were developed to analyze the influence of these systems on lateral dynamics.Additionally,a hierarchical control architecture was designed to control the vehicle’s lateral stability.The effectiveness of the proposed control scheme was demonstrated and validated through hardware-in-the-loop(HIL)tests and real-world vehicle testing.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
Self-oscillating chemomechanical redox-responsive poly(Nisopropylacrylamide)gels containing terpyridine-iron complexes were developed.Two types of gels containing the complexes as pendant groups or as cross-linking ag...Self-oscillating chemomechanical redox-responsive poly(Nisopropylacrylamide)gels containing terpyridine-iron complexes were developed.Two types of gels containing the complexes as pendant groups or as cross-linking agents were designed and prepared.All the obtained gels exhibited pronounced chemomechanical oscillations resulting from the Belousov-Zhabotinsky reaction within their structure.They periodically swelled and contracted upon oxidation and reduction of the terpyridine-iron complex under mild conditions and at low mineral acid concentrations.The periodic changes in linear dimensions of the gels reached 17%.It was found that the propagating chemical wave moved along the cylindrical gel causing autonomous peristaltic motion due to local swelling.Based on the obtained gel,a levertype actuator was created demonstrating periodic lifting of the lever.The gels were characterized through scanning electron microscopy,and the dependence of their structure and chemomechanical properties on the catalyst concentration was investigated.These gels hold great promise for creating soft and self-moving muscle-like actuators,devices capable of transmitting and interpreting signals through traveling chemical waves,and sensor systems that respond to changes in oxidation-reduction states.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
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
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
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National Natural Science Foundation for Distinguished Young Scholars of China （50825502）
文摘The electro-hydrostatic actuator （EHA） is a kind of power-by-wire （PBW） actuator that converts the electrical power into localized hydraulic power for flight control. By removing the central hydraulic power supply together with hydraulic pipes, an EHA＇s reliability and efficiency are greatly improved but its frequency width and stiffness decreased. To overcome the drawback, this article proposes a novel structure of EHA associated with a power regulator. Composed of a high-pressure accumulator and a proportional valve, it can store and harness the hydraulic power flexibly according to the changing control requirements. The concept of transferred volume is put forward to estimate the capability of the power regulator. The actuator output position can be kept fixed with a hydraulic lock. The compounded control is specially developed to ensure the actuator system to operate in a correct manner. The simulation results indicate that the new-brand actuator results in efficient expanding of the system frequency width with an optimal power supply.
基金supported by the National Natural Science Foundation of China(Nos.51620105010,51675019 and 51575019)the National Basic Research Program of China(No.2014CB046402)+1 种基金the ‘‘111" Projectthe Excellence Foundation of BUAA for PhD Students
文摘This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under highspeed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded.
文摘The integrated electro-hydrostatic actuator （EHA） with variable displacement and variable rotation speed is researched. In the system, the output of the actuator is changed by controlling the rotationspeed of the brushless DC servomotor and the displacement of the servopump. The mathematical model described in state-space model is created. The system characteristics are studied based on the point of multiplicative dual-variable. And the basic method of control of the system is presented.
基金co-supported by the National Natural Science Foundation of China (No. 51890882)National Key Research and Development Program of China (No. 2018YFB2000702)
文摘The electro-hydrostatic actuator(EHA)used in more electric aircraft(MEA)has been extensively studied due to its advantages of high reliability and high integration.However,this high integration results in a small heat dissipation area,leading to high-temperature problems.Generally,to reduce the temperature,a wet cooling method of using the pump leakage oil to cool the motor is adopted,which can also increase the difficulty of accurately predicting the system temperature in the early design stage.To solve this problem,a dynamic coupling thermal model of a wet EHA is proposed in this paper.In particular,the leakage oil of the pump is used as a coupling item between the electrical system and the hydraulic system.Then,an improved T-equivalent block model is proposed to address the uneven distribution of axial oil temperature inside the motor,and the control node method is applied to hydraulic system thermal modeling.Meanwhile,a dynamic coupling thermal model is developed that enables a dynamic evaluation of the wet EHA temperature.Then,experimental prototypes of wet motor and wet EHA are developed,while the temperature response of the wet motor at different rotation speeds and different loads and the temperature response of the wet EHA at no-load condition were verified experimentally at room temperature,respectively.The maximum temperature difference between the experimental and theoretical results of the wet motor as well as the experimental and theoretical results of the wet EHA is less than 8℃.These test results indicate that the dynamic coupling thermal model is valid and demonstrate that the thermal coupling modeling method proposed in this paper can provide a basis for the detailed thermal design of EHA.
基金financial supports from the National Basic Research Program of China(973 Program)(No.2014CB046403)the National Natural Science Foundation of China(No.1737110)
文摘The speed of an Electro-Hydrostatic Actuator(EHA) pump can recently reach 20000 r/min, and its churning losses increase obviously with an increasing speed, which results in low efficiency and thus increasing heat in aircraft EHA systems. In order to reduce churning losses at high speeds, more attention should be given to the design of an insert. In this paper, the effect of an insert with different design parameters on churning losses is investigated through Computational Fluid Dynamics(CFD) simulation and experiments by calculating the difference between churning losses torques of the test pump with and without the insert based on a high-speed churning losses test rig.Analytical results show that the gap between the insert and the cylinder is critical for churning losses reduction. It is found that the churning losses of the test pump can be reduced with a decreasing gap between the cylinder block and the insert at high speeds. This is because the insert can decrease the turbulence occurrence at high speeds. The results can be used for flow field analysis and optimization of the high-speed EHA pump and provide a new method for improving efficiency of high-speed EHA pumps.
基金financially supported by the National Natural Science Foundation of China(No’s.51375029 and 51775013).
文摘The variable pump displacement and variable motor speed electro-hydrostatic actuator(EHA),one of the three types of EHAs,has advantages such as short response time,flexible speed regulation,and high efficiency.However,the nonlinearity of its double-input single-output system poses a great challenge for system control.This study proposes a novel EHA with adaptive pump displacement and variable motor speed(EHA-APVM).A closed-loop position is realized using a servomotor.Moreover,the displacement varies with the system pressure;thus,the EHA-APVM is a single-input and single-output system.Firstly,the working principles of the EHA-APVM and the pump used in the system are introduced.Secondly,a nonlinear mathematical model of the proposed EHA-APVM control system is established,and a feedback back-stepping(FBBS)control algorithm is introduced to transform the complex nonlinear system into a linear system on the basis of the back-stepping control theory.Finally,simulation results prove that the EHA-APVM has a quick response and high robustness to variations of the load and the pump displacement.In this work,the size and weight of the motor are significantly reduced because the maximum power requirement is reduced,which is very beneficial for using the actuator in airborne equipment.
基金This work was supported in part by National Natural Science Foundation of China(Nos.52177028 and U2141226)in part by Major Program of the National Natural Science Foundation of China(No.51890882)in part by Aeronautical Science Foundation of China(No.201907051002).
文摘To improve the power density and simplify the seal structure,the Wet-Type Permanent Magnet Synchronous Motor(WTPMSM)technique has been applied to aerospace Electro-Hydrostatic Actuators(EHA).In a WTPMSM,the stator and the rotor are both immersed in the aviation hydraulic oil.Although the heat dissipation performance of the WTPMSM can be enhanced,the aviation hydraulic oil will cost an extra oil frictional loss in the narrow airgap of the WTPMSM.This paper proposes an accurate oil frictional loss model for the WTPMSM,in which the wide speed range(0–20 kr/min)and the narrowness of the airgap(0.5–1.5 mm)are its features.Firstly,the mechanism of the oil frictional loss in the airgap of the WTPMSM is revealed.Then an accurate oil frictional loss model is proposed considering the nonlinear influence caused by the Taylor vortex.Furthermore,the influence of motor dimensions on oil frictional loss is analyzed.Finally,the proposed oil frictional loss model is verified by experiments,which provides a guideline for engineers to follow in the WTPMSM design.
基金supported by the National Natural Science Foundation of China(Nos.51620105010,51675019,51575019)the National Basic Research Program of China(No.2014CB046402)the Program 111 of China
文摘The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator（LEHA）. Rather than the traditional statistical methods based on degradation data, the method proposed in this paper firstly analyzes the dominant progressive failure mode of the LEHA based on the working principle and working conditions of the LEHA. The Computational Fluid Dynamics（CFD） method, combining the turbulent theory and the micro erosion principle, is used to establish an erosion model of the rectification mechanism. The erosion rates for different port openings, under a time-varying flow field, are obtained. The piecewise linearization method is applied to update the concentration of contaminated particles within the LEHA, in order to gain insight into the erosion degradation process at various stages of degradation. The main contribution of the proposed model is the application of the dynamic concentration of contamination particles in erosion analysis of Electro-Hydraulic Servo Valves（EHSVs）, throttle valves, spool valves, and needle valves. The effects of system parameters and working conditions on component wear are analyzed by simulations. The results of the proposed model match the expected degradation process.
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 National Nature Science Foundation of China(Grant Nos.52325212,52372394)National Key Research and Development Program of China(Grant Nos.2022YFE0117100,2021YFB2501201)+1 种基金Industry-University-Research Innovation Fund for Chinese Universities(Grand No.2024HT010)Fundamental Research Funds for the Central Universities.
文摘Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control.Modern chassis-by-wire systems manage an increasing number of heterogeneous chassis execution systems,including distributed drive,all-wheel drive(AWD),brake-by-wire(BBW),steer-by-wire(SBW),rear-wheel steering(RWS),active stabilizer bar(ASB)and active suspension system(ASS),greatly enhancing the controllable degrees of freedom compared to conventional chassis configurations.To advance research in chassis domain control,it is essential to understand how these heterogeneous execution systems influence vehicle dynamics.This paper focuses on the modeling and analysis of the lateral,longitudinal,and vertical chassis control and execution systems,-as well as their impact on vehicle lateral motion.Using a vehicle simulation platform,both the vehicle dynamics model and the individual dynamics models of each execution system were developed to analyze the influence of these systems on lateral dynamics.Additionally,a hierarchical control architecture was designed to control the vehicle’s lateral stability.The effectiveness of the proposed control scheme was demonstrated and validated through hardware-in-the-loop(HIL)tests and real-world vehicle testing.
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supported by the grants the Russian Science Foundation,RSF 24-11-00347。
文摘Self-oscillating chemomechanical redox-responsive poly(Nisopropylacrylamide)gels containing terpyridine-iron complexes were developed.Two types of gels containing the complexes as pendant groups or as cross-linking agents were designed and prepared.All the obtained gels exhibited pronounced chemomechanical oscillations resulting from the Belousov-Zhabotinsky reaction within their structure.They periodically swelled and contracted upon oxidation and reduction of the terpyridine-iron complex under mild conditions and at low mineral acid concentrations.The periodic changes in linear dimensions of the gels reached 17%.It was found that the propagating chemical wave moved along the cylindrical gel causing autonomous peristaltic motion due to local swelling.Based on the obtained gel,a levertype actuator was created demonstrating periodic lifting of the lever.The gels were characterized through scanning electron microscopy,and the dependence of their structure and chemomechanical properties on the catalyst concentration was investigated.These gels hold great promise for creating soft and self-moving muscle-like actuators,devices capable of transmitting and interpreting signals through traveling chemical waves,and sensor systems that respond to changes in oxidation-reduction states.
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.
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.
