The contour error was analyzed based on CNC multi-axis motion control, the contour error model was obtained focused on beeline and different radius of curvature and common contour of curve, for a CNC biaxial motion co...The contour error was analyzed based on CNC multi-axis motion control, the contour error model was obtained focused on beeline and different radius of curvature and common contour of curve, for a CNC biaxial motion control system and the mechanism of producing contour error and the relationship between tracking error and contour error were presented. The theoretical and practical significance of modeling error and controlling error in motion control systems was carried out.展开更多
The existing research of the motion optimization of multi-axis machine tools is mainly based on geometric and kinematic constraints, which aim at obtaining minimum-time trajectories and finding obstacle-free paths. In...The existing research of the motion optimization of multi-axis machine tools is mainly based on geometric and kinematic constraints, which aim at obtaining minimum-time trajectories and finding obstacle-free paths. In motion optimization, the stiffness characteristics of the whole machining system, including machine tool and cutter, are not considered. The paper presents a new method to establish a general stiffness model of multi-axis machining system. An analytical stiffness model is established by Jacobi and point transformation matrix method. Based on the stiffness model, feed-direction stiffness index is calculated by the intersection of force ellipsoid and the cutting feed direction at the cutter tip. The stiffness index can help analyze the stiffness performance of the whole machining system in the available workspace. Based on the analysis of the stiffness performance, multi-axis motion optimization along tool paths is accomplished by mixed programming using Matlab and Visual C＋＋. The effectiveness of the motion optimization method is verified by the experimental research about the machining performance of a 7-axis 5-linkage machine tool. The proposed research showed that machining stability and production efficiency can be improved by multi-axis motion optimization based on the anisotropic force ellipsoid of the whole machining system.展开更多
This paper presents a fuzzy control algorithm applied to the position control of a multi-axis motion platform to achieve high precision motion control of the multi-axis motion platform.A LabVIEW-based multi-axis motio...This paper presents a fuzzy control algorithm applied to the position control of a multi-axis motion platform to achieve high precision motion control of the multi-axis motion platform.A LabVIEW-based multi-axis motion control system is designed.This system controls stepper motors using trapezoidal acceleration/deceleration pulse types and fuzzy control algorithms,which effectively avoids mechanical jitter and loss of step in the process of multi-angle motion of the stepper motor,and achieves accurate control of the stepper motor.The TCP/IP(transmission control protocol/internet protocol)communication protocol is used,so that data are output stably and not lost in the process of transmission and communication,achieving the purpose of interconnection of different systems and remote control of equipment.This control system has been tested to maintain a high level of stability and repeatability during actual operation.展开更多
An improved RRT∗algorithm,referred to as the AGP-RRT∗algorithm,is proposed to address the problems of poor directionality,long generated paths,and slow convergence speed in multi-axis robotic arm path planning.First,a...An improved RRT∗algorithm,referred to as the AGP-RRT∗algorithm,is proposed to address the problems of poor directionality,long generated paths,and slow convergence speed in multi-axis robotic arm path planning.First,an adaptive biased probabilistic sampling strategy is adopted to dynamically adjust the target deviation threshold and optimize the selection of random sampling points and the direction of generating new nodes in order to reduce the search space and improve the search efficiency.Second,a gravitationally adjustable step size strategy is used to guide the search process and dynamically adjust the step-size to accelerate the search speed of the algorithm.Finally,the planning path is processed by pruning,removing redundant points and path smoothing fitting using cubic B-spline curves to improve the flexibility of the robotic arm.Through the six-axis robotic arm path planning simulation experiments on the MATLAB platform,the results show that the AGP-RRT∗algorithm reduces 87.34%in terms of the average running time and 40.39%in terms of the average path cost;Meanwhile,under two sets of complex environments A and B,the average running time of the AGP-RRT∗algorithm is shortened by 94.56%vs.95.37%,and the average path cost is reduced by 55.28%vs.47.82%,which proves the effectiveness of the AGP-RRT∗algorithm in improving the efficiency of multi-axis robotic arm path planning.展开更多
In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):104...In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].展开更多
Internal learning-based video inpainting methods have shown promising results by exploiting the intrinsic properties of the video to fill in the missing region without external dataset supervision.However,existing int...Internal learning-based video inpainting methods have shown promising results by exploiting the intrinsic properties of the video to fill in the missing region without external dataset supervision.However,existing internal learning-based video inpainting methods would produce inconsistent structures or blurry textures due to the insufficient utilisation of motion priors within the video sequence.In this paper,the authors propose a new internal learning-based video inpainting model called appearance consistency and motion coherence network(ACMC-Net),which can not only learn the recurrence of appearance prior but can also capture motion coherence prior to improve the quality of the inpainting results.In ACMC-Net,a transformer-based appearance network is developed to capture global context information within the video frame for representing appearance consistency accurately.Additionally,a novel motion coherence learning scheme is proposed to learn the motion prior in a video sequence effectively.Finally,the learnt internal appearance consistency and motion coherence are implicitly propagated to the missing regions to achieve inpainting well.Extensive experiments conducted on the DAVIS dataset show that the proposed model obtains the superior performance in terms of quantitative measurements and produces more visually plausible results compared with the state-of-the-art methods.展开更多
With the rapid development of wearable electronic skin technology, flexible strain sensors have shown great application prospects in the fields of human motion and physiological signal detection, medical diagnostics, ...With the rapid development of wearable electronic skin technology, flexible strain sensors have shown great application prospects in the fields of human motion and physiological signal detection, medical diagnostics, and human-computer interaction owing to their outstanding sensing performance. This paper reports a strain sensor with synergistic conductive network, consisting of stable carbon nanotube dispersion (CNT) layer and brittle MXene layer by dip-coating and electrostatic self-assembly method, and breathable three-dimensional (3D) flexible substrate of thermoplastic polyurethane (TPU) fibrous membrane prepared through electrospinning technology. The MXene/CNT@PDA-TPU (MC@p-TPU) flexible strain sensor had excellent air permeability, wide operating range (0–450 %), high sensitivity (Gauge Factor, GFmax = 8089.7), ultra-low detection limit (0.05 %), rapid response and recovery times (40 ms/60 ms), and excellent cycle stability and durability (10,000 cycles). Given its superior strain sensing capabilities, this sensor can be applied in physiological signals detection, human motion pattern recognition, and driving exoskeleton robots. In addition, MC@p-TPU fibrous membrane also exhibited excellent photothermal conversion performance and can be used as a wearable photo-heater, which has far-reaching application potential in the photothermal therapy of human joint diseases.展开更多
In this study,we present a unified sparsity-driven framework that significantly enhances motion deblurring performance by integrating two key components:a custom-designed dataset and a low-rank module(LRM).This framew...In this study,we present a unified sparsity-driven framework that significantly enhances motion deblurring performance by integrating two key components:a custom-designed dataset and a low-rank module(LRM).This framework leverages the inherent sparsity of per-pixel blur kernels to bolster both deblurring accuracy and model interpretability.Firstly,we propose an adaptive-basis decomposition-based deblurring(ADD)approach,which constructs a tailored training dataset to enhance the generalization capacity of the deblurring network.The ADD framework adaptively decomposes motion blur into sparse basis elements,effectively addressing the intricacies associated with non-uniform blurs.Secondly,an LRM is proposed to improve the interpretability of deblurring models as a plug-and-play module,primarily designed to identify and harness the intrinsic sparse features in sharp images.A series of ablation studies have been conducted to substantiate the synergistic advantages of combining the proposed ADD with the LRM for overall improvement in deblurring efficacy.Subsequently,we empirically demonstrate through rigorous experimentation that incorporating the LRM into an existing Uformer network leads to substantial enhancement in reconstruction performance.This integration yields a sparsity-guided low-rank network(SGLRN).Operating under the overarching principle of sparsity,SGLRN consistently outperforms state-of-the-art methods across multiple standard deblurring benchmarks.Comprehensive experimental results,assessed through quantitative metrics and qualitative visual evaluations,provide compelling evidence of its effectiveness.The overall deblurring results are available at Google Drive.展开更多
Piezoelectric actuators are widely utilized in positioning systems to realize nano-scale resolution. However, the backward motion always generates for some piezoelectric actuators, which reduces the working efficiency...Piezoelectric actuators are widely utilized in positioning systems to realize nano-scale resolution. However, the backward motion always generates for some piezoelectric actuators, which reduces the working efficiency. Bionic motions have already been employed in the field of piezoelectric actuators to realize better performance. By imitating the movement form of seals, seal type piezoelectric actuator is capable to realize large operating strokes easily. Nevertheless, the conventional seal type piezoelectric actuator has a complicated structure and control system, which limits further applications. Hence, an improved bionic piezoelectric actuator is proposed to realize a long motion stroke and eliminate backward movement with a simplified structure and control method in this study. The composition and motion principle of the designed actuator are discussed, and the performance is investigated with simulations and experiments. Results confirm that the presented actuator effectively realizes the linear movement that has a large working stroke stably without backward motion. The smallest stepping displacement ΔL is 0.2 μm under 1 Hz and 50 V. The largest motion speed is 900 μm/s with 900 Hz and 120 V. The largest vertical and horizontal load are 250 g and 12 g, respectively. This work shows that the improved bionic piezoelectric actuator is feasible for eliminating backward motion and has a great working ability.展开更多
This article centers on The Call of the Wild,an English novel by American author Jack London,alongside two Chinese translations by Dajie Liu and Menglin Zhang,and Rongyue Liu.Seventy sentences containing motion events...This article centers on The Call of the Wild,an English novel by American author Jack London,alongside two Chinese translations by Dajie Liu and Menglin Zhang,and Rongyue Liu.Seventy sentences containing motion events and their corresponding translations were randomly selected for analysis.The study focuses on the primary elements of motion events-manner,path,and ground-and examines their Chinese translations through the lens of Skopos theory.Skopos theory emphasizes whether translators can adopt appropriate translation strategies according to various contextual factors during the translation process.Compared to verb-framed languages,satellite-framed languages possess a richer vocabulary for manner verbs,express more detailed manner information,use more satellite words to indicate paths,and incorporate more background information.Verb-framed languages,by contrast,typically express manner information only when necessary and tend to include less background information.The analysis reveals that both Chinese translations embody the core principle of Skopos theory:translation strategies are determined by their purpose.To fulfill the novel’s translation objectives,the translators adeptly adjust their strategies for motion event components based on different contextual needs.It is noted that the Chinese translations do not fully retain the characteristics of English as a typical satellite-framed language.This observation aligns with Skopos theory’s purpose-oriented approach,which prioritizes translation goals over strict adherence to source text characteristics.展开更多
Shape memory alloy(SMA)bars are currently preferred over elastomeric seismic isolators due to the elimination of degradation within effective damping and stiffness factors during the cyclic response of an isolation sy...Shape memory alloy(SMA)bars are currently preferred over elastomeric seismic isolators due to the elimination of degradation within effective damping and stiffness factors during the cyclic response of an isolation system.These bars could also be used to prevent the functionality of the isolator units from failing due to large deformations.This study aims to investigate the performance of a high damping rubber bearing(HDRB)isolator that is combined with two different types of SMA bars,i.e.,Nickel-Titanium(Ni-Ti)and Copper-Aluminum-Beryllium(Cu-Al-Be),subjected to near-fault ground motions that are characterized with forward directivity and fling step effects.To achieve this objective,a self-centering material with flag-shape,force-deformation hysteresis was utilized to simulate the behavior of SMA bars in OpenSees.A single degree of freedom(SDOF)system representing an isolated one-story shear building was developed to conduct nonlinear analysis under selected ground motions.The SMA bars were introduced as an X-shape within the model and were connected diagonally to the top and bottom of the isolator.Results showed that the HDRB system’s hysteretic response under near-fault ground accelerations experiences significant degradation,especially when near-fault motions involve the fling step effect.It was demonstrated that SMA bars effectively reduce large displacement observed in HDRB systems under near-fault earthquakes.Comparing the results of the base-isolated HDRB and SMA-HDRB subjected to selected ground motions demonstrated that maximum displacement was found to be significantly reduced by an average of 79%when SMA bars were used.Incorporating SMA bars with a larger diameter significantly improves the efficiency of SMA HDRB systems,and a reduction in maximum displacements is more pronounced for fling step,near-fault ground motions.展开更多
Microrobots powered by an external magnetic field could be used for sophisticated medical applications such as cell treatment,micromanipulation,and noninvasive surgery inside the body.Untethered microrobot application...Microrobots powered by an external magnetic field could be used for sophisticated medical applications such as cell treatment,micromanipulation,and noninvasive surgery inside the body.Untethered microrobot applications can benefit from haptic technology and telecommunication,enabling telemedical micro-manipulation.Users can manipulate the microrobots with haptic feedback by interacting with the robot operating system remotely in such applications.Artificially created haptic forces based on wirelessly transmitted data and model-based guidance can aid human operators with haptic sensations while manipulating microrobots.The system presented here includes a haptic device and a magnetic tweezer system linked together using a network-based teleoperation method with motion models in fluids.The magnetic microrobots can be controlled remotely,and the haptic interactions with the remote environment can be felt in real time.A time-domain passivity controller is applied to overcome network delay and ensure stability of communication.This study develops and tests a motion model for microrobots and evaluates two image-based 3D tracking algorithms to improve tracking accuracy in various Newtonian fluids.Additionally,it demonstrates that microrobots can group together to transport multiple larger objects,move through microfluidic channels for detailed tasks,and use a novel method for disassembly,greatly expanding their range of use in microscale operations.Remote medical treatment in multiple locations,remote delivery of medication without the need for physical penetration of the skin,and remotely controlled cell manipulations are some of the possible uses of the proposed technology.展开更多
Legged robots have always been a focal point of research for scholars domestically and internationally.Compared to other types of robots,quadruped robots exhibit superior balance and stability,enabling them to adapt e...Legged robots have always been a focal point of research for scholars domestically and internationally.Compared to other types of robots,quadruped robots exhibit superior balance and stability,enabling them to adapt effectively to diverse environments and traverse rugged terrains.This makes them well-suited for applications such as search and rescue,exploration,and transportation,with strong environmental adaptability,high flexibility,and broad application prospects.This paper discusses the current state of research on quadruped robots in terms of development status,gait trajectory planning methods,motion control strategies,reinforcement learning applications,and control algorithm integration.It highlights advancements in modeling,optimization,control,and data-driven approaches.The study identifies the adoption of efficient gait planning algorithms,the integration of reinforcement learning-based control technologies,and data-driven methods as key directions for the development of quadruped robots.The aim is to provide theoretical references for researchers in the field of quadruped robotics.展开更多
On the basis of the model tests,this paper explores the coupled hydrodynamic performance of the moonpool and the hull.This study aims to compare and analyze the variation in the hull heave response between the piston ...On the basis of the model tests,this paper explores the coupled hydrodynamic performance of the moonpool and the hull.This study aims to compare and analyze the variation in the hull heave response between the piston resonance state of the moonpool under wave excitation and the non-resonance state of the moonpool under wave-current excitation.A novel damping device specifically designed and fabricated for stepped moonpools has been developed.Before and after the installation of the damping device,the free surface response characteristics of the moonpool and heave motion response characteristics of the hull are compared.The findings show a clear correlation between the current speed and heave response characteristics of the hull.During the seakeeping design phase of the drilling vessel,the current speed is an additional critical factor that cannot be disregarded,alongside the moonpool effect.A correlation exists between the fluid dynamics occurring within the moonpool and the heave motion of the vessel hull.A reduction in the amplitude of the motion of the moonpool water results in a decrease in the heave motion of the hull.This study provides a reference for alleviating the seakeeping of a drill ship’s heave response and enhancing the safety and efficiency of the operation.展开更多
This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation freq...This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation frequencies.Results reveal that the eigenfrequencies vary spatially due to distinct oscillation modes occurring at different droplet locations.Notably,the fundamental eigenfrequency decreases with reducing droplet volume,while droplet viscosity exerts minimal influence on this frequency.Prior to the onset of motion,the dynamic contact angle consistently remains between the advancing and receding angles.The inertial forces generated by droplet oscillation are found to be significantly greater than the adhesion forces,indicating that classical static models are inadequate for capturing inertial contributions to droplet motion.These findings offer new insights into the role of oscillatory behavior in influencing the dynamics of droplet motion,and contribute to a more detailed understanding of wind-driven droplet transport phenomena.展开更多
This study aimed to identify and compensate for the geometric errors of the double swiveling axes in a five-axis computer numerical control(CNC)machining center.Hence,a three-dimensional coordinate calculation algorit...This study aimed to identify and compensate for the geometric errors of the double swiveling axes in a five-axis computer numerical control(CNC)machining center.Hence,a three-dimensional coordinate calculation algorithm for a measured point with additional rotational rigid body motion constraints is proposed.The motion constraints of the rotational rigid body were analyzed,and a mathematical model of the measured point algorithm in the swiveling axes was established.The Levenberg-Marquard method was used to solve the nonlinear superstatically determined equations.The spatial coordinate error was used to separate the spatial deviation of the measured point.An identification model of the position-independent and position-dependent geometric errors was established.The three-dimensional coordinate-solving algorithm of the measured point in the swiveling axis and geometric error identification method based on the Monte Carlo method were analyzed numerically.Geometric error measurement and cutting experiments were performed on a VMC25100U five-axis machining center,which integrated two swiveling axes.Geometric errors of the A-and B-axes were identified and measured experimentally.The angular positioning errors before and after compensation were measured using a laser interferometer,which verified the effectiveness of the proposed algorithm.A cutting experiment of a round table part was performed.The shape and position accuracy of the processed part before and after compensation were detected using a coordinate measuring machine.It verified that the geometric error of the swiveling axis was effectively compensated by the algorithm proposed herein.展开更多
The flocculation behavior of carbon black (CB)-filled isoprene rubber (IR) nanocomposites was systematically investigated under both dynamic and static conditions to unravel the distinct mechanisms governing filler ne...The flocculation behavior of carbon black (CB)-filled isoprene rubber (IR) nanocomposites was systematically investigated under both dynamic and static conditions to unravel the distinct mechanisms governing filler network evolution.Under dynamic conditions,small oscillatory shear strains (0.1%) significantly enhanced filler particle motion,leading to pronounced agglomeration and a flocculation degree of about 4.3MPa at 145℃.In contrast,static flocculation exhibited a fundamentally different mechanism dominated by polymer chain dynamics,which is driven mainly by thermal activation.Radial distribution function (RDF) analysis of transmission electron microscopy (TEM) images revealed a slight decrease (2 nm) in the interparticle distance peak after static annealing at 100℃ for 7 h,indicating localized motion of CB particles.However,the overall filler network remained stable,with no significant agglomeration observed.The increase in bound rubber content from about 23% to 28% with rising temperature further confirmed the dominant role of polymer chain adsorption and interfacial reinforcement in static flocculation.These findings highlight the critical influence of external strain on filler network formation and provide new insights into the polymer-dominated mechanism of static flocculation.The results offer practical guidance for optimizing the storage and processing of rubber nanocomposites,particularly in applications where static flocculation during prolonged storage is a concern.展开更多
基金supported by the Science Foundation of the Education Office of Gansu Province of Chinaunder Grant No.0914-01
文摘The contour error was analyzed based on CNC multi-axis motion control, the contour error model was obtained focused on beeline and different radius of curvature and common contour of curve, for a CNC biaxial motion control system and the mechanism of producing contour error and the relationship between tracking error and contour error were presented. The theoretical and practical significance of modeling error and controlling error in motion control systems was carried out.
基金supported by National Natural Science Foundation of China (Grant No. 51075168)National Basic Research Program of China (973 Program, Grant No. 2011CB706803)National Hi-tech Research and Development Program of China (863 Program, Grant No. 2009AA04Z149)
文摘The existing research of the motion optimization of multi-axis machine tools is mainly based on geometric and kinematic constraints, which aim at obtaining minimum-time trajectories and finding obstacle-free paths. In motion optimization, the stiffness characteristics of the whole machining system, including machine tool and cutter, are not considered. The paper presents a new method to establish a general stiffness model of multi-axis machining system. An analytical stiffness model is established by Jacobi and point transformation matrix method. Based on the stiffness model, feed-direction stiffness index is calculated by the intersection of force ellipsoid and the cutting feed direction at the cutter tip. The stiffness index can help analyze the stiffness performance of the whole machining system in the available workspace. Based on the analysis of the stiffness performance, multi-axis motion optimization along tool paths is accomplished by mixed programming using Matlab and Visual C＋＋. The effectiveness of the motion optimization method is verified by the experimental research about the machining performance of a 7-axis 5-linkage machine tool. The proposed research showed that machining stability and production efficiency can be improved by multi-axis motion optimization based on the anisotropic force ellipsoid of the whole machining system.
文摘This paper presents a fuzzy control algorithm applied to the position control of a multi-axis motion platform to achieve high precision motion control of the multi-axis motion platform.A LabVIEW-based multi-axis motion control system is designed.This system controls stepper motors using trapezoidal acceleration/deceleration pulse types and fuzzy control algorithms,which effectively avoids mechanical jitter and loss of step in the process of multi-angle motion of the stepper motor,and achieves accurate control of the stepper motor.The TCP/IP(transmission control protocol/internet protocol)communication protocol is used,so that data are output stably and not lost in the process of transmission and communication,achieving the purpose of interconnection of different systems and remote control of equipment.This control system has been tested to maintain a high level of stability and repeatability during actual operation.
基金supported by Foundation of key Laboratory of AI and Information Processing of Education Department of Guangxi(No.2022GXZDSY002)(Hechi University),Foundation of Guangxi Key Laboratory of Automobile Components and Vehicle Technology(Nos.2022GKLACVTKF04,2023GKLACVTZZ06)。
文摘An improved RRT∗algorithm,referred to as the AGP-RRT∗algorithm,is proposed to address the problems of poor directionality,long generated paths,and slow convergence speed in multi-axis robotic arm path planning.First,an adaptive biased probabilistic sampling strategy is adopted to dynamically adjust the target deviation threshold and optimize the selection of random sampling points and the direction of generating new nodes in order to reduce the search space and improve the search efficiency.Second,a gravitationally adjustable step size strategy is used to guide the search process and dynamically adjust the step-size to accelerate the search speed of the algorithm.Finally,the planning path is processed by pruning,removing redundant points and path smoothing fitting using cubic B-spline curves to improve the flexibility of the robotic arm.Through the six-axis robotic arm path planning simulation experiments on the MATLAB platform,the results show that the AGP-RRT∗algorithm reduces 87.34%in terms of the average running time and 40.39%in terms of the average path cost;Meanwhile,under two sets of complex environments A and B,the average running time of the AGP-RRT∗algorithm is shortened by 94.56%vs.95.37%,and the average path cost is reduced by 55.28%vs.47.82%,which proves the effectiveness of the AGP-RRT∗algorithm in improving the efficiency of multi-axis robotic arm path planning.
基金Supported by NSFC(Nos.11661025,12161024)Natural Science Foundation of Guangxi(Nos.2020GXNSFAA159118,2021GXNSFAA196045)+2 种基金Guangxi Science and Technology Project(No.Guike AD20297006)Training Program for 1000 Young and Middle-aged Cadre Teachers in Universities of GuangxiNational College Student's Innovation and Entrepreneurship Training Program(No.202110595049)。
文摘In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].
基金Shenzhen Science and Technology Programme,Grant/Award Number:JCYJ202308071208000012023 Shenzhen sustainable supporting funds for colleges and universities,Grant/Award Number:20231121165240001Guangdong Provincial Key Laboratory of Ultra High Definition Immersive Media Technology,Grant/Award Number:2024B1212010006。
文摘Internal learning-based video inpainting methods have shown promising results by exploiting the intrinsic properties of the video to fill in the missing region without external dataset supervision.However,existing internal learning-based video inpainting methods would produce inconsistent structures or blurry textures due to the insufficient utilisation of motion priors within the video sequence.In this paper,the authors propose a new internal learning-based video inpainting model called appearance consistency and motion coherence network(ACMC-Net),which can not only learn the recurrence of appearance prior but can also capture motion coherence prior to improve the quality of the inpainting results.In ACMC-Net,a transformer-based appearance network is developed to capture global context information within the video frame for representing appearance consistency accurately.Additionally,a novel motion coherence learning scheme is proposed to learn the motion prior in a video sequence effectively.Finally,the learnt internal appearance consistency and motion coherence are implicitly propagated to the missing regions to achieve inpainting well.Extensive experiments conducted on the DAVIS dataset show that the proposed model obtains the superior performance in terms of quantitative measurements and produces more visually plausible results compared with the state-of-the-art methods.
基金supported by the National Natural Science Foundation of China(Nos.52373093 and 12072325)the Outstanding Youth Fund of Henan Province(No.242300421062)+1 种基金National Key R&D Program of China(No.2019YFA0706802)the 111 project(No.D18023).
文摘With the rapid development of wearable electronic skin technology, flexible strain sensors have shown great application prospects in the fields of human motion and physiological signal detection, medical diagnostics, and human-computer interaction owing to their outstanding sensing performance. This paper reports a strain sensor with synergistic conductive network, consisting of stable carbon nanotube dispersion (CNT) layer and brittle MXene layer by dip-coating and electrostatic self-assembly method, and breathable three-dimensional (3D) flexible substrate of thermoplastic polyurethane (TPU) fibrous membrane prepared through electrospinning technology. The MXene/CNT@PDA-TPU (MC@p-TPU) flexible strain sensor had excellent air permeability, wide operating range (0–450 %), high sensitivity (Gauge Factor, GFmax = 8089.7), ultra-low detection limit (0.05 %), rapid response and recovery times (40 ms/60 ms), and excellent cycle stability and durability (10,000 cycles). Given its superior strain sensing capabilities, this sensor can be applied in physiological signals detection, human motion pattern recognition, and driving exoskeleton robots. In addition, MC@p-TPU fibrous membrane also exhibited excellent photothermal conversion performance and can be used as a wearable photo-heater, which has far-reaching application potential in the photothermal therapy of human joint diseases.
基金supported by the National Natural Science Foundation of China(No.62206143)the Key Research and Development and Promotion Special Project in Henan Province(Nos.222102210141 and 232102211015)。
文摘In this study,we present a unified sparsity-driven framework that significantly enhances motion deblurring performance by integrating two key components:a custom-designed dataset and a low-rank module(LRM).This framework leverages the inherent sparsity of per-pixel blur kernels to bolster both deblurring accuracy and model interpretability.Firstly,we propose an adaptive-basis decomposition-based deblurring(ADD)approach,which constructs a tailored training dataset to enhance the generalization capacity of the deblurring network.The ADD framework adaptively decomposes motion blur into sparse basis elements,effectively addressing the intricacies associated with non-uniform blurs.Secondly,an LRM is proposed to improve the interpretability of deblurring models as a plug-and-play module,primarily designed to identify and harness the intrinsic sparse features in sharp images.A series of ablation studies have been conducted to substantiate the synergistic advantages of combining the proposed ADD with the LRM for overall improvement in deblurring efficacy.Subsequently,we empirically demonstrate through rigorous experimentation that incorporating the LRM into an existing Uformer network leads to substantial enhancement in reconstruction performance.This integration yields a sparsity-guided low-rank network(SGLRN).Operating under the overarching principle of sparsity,SGLRN consistently outperforms state-of-the-art methods across multiple standard deblurring benchmarks.Comprehensive experimental results,assessed through quantitative metrics and qualitative visual evaluations,provide compelling evidence of its effectiveness.The overall deblurring results are available at Google Drive.
基金supported by The Key Science and Technology Plan Project of Jinhua City,China:2023-3-084,2023-2-011Zhejiang Provincial"Revealing the list and taking command"Project of China KYH06Y22349Open Fund Project of Key Laboratory of CNC Equipment reliability,Ministry of Education JLU-cncr-202407.
文摘Piezoelectric actuators are widely utilized in positioning systems to realize nano-scale resolution. However, the backward motion always generates for some piezoelectric actuators, which reduces the working efficiency. Bionic motions have already been employed in the field of piezoelectric actuators to realize better performance. By imitating the movement form of seals, seal type piezoelectric actuator is capable to realize large operating strokes easily. Nevertheless, the conventional seal type piezoelectric actuator has a complicated structure and control system, which limits further applications. Hence, an improved bionic piezoelectric actuator is proposed to realize a long motion stroke and eliminate backward movement with a simplified structure and control method in this study. The composition and motion principle of the designed actuator are discussed, and the performance is investigated with simulations and experiments. Results confirm that the presented actuator effectively realizes the linear movement that has a large working stroke stably without backward motion. The smallest stepping displacement ΔL is 0.2 μm under 1 Hz and 50 V. The largest motion speed is 900 μm/s with 900 Hz and 120 V. The largest vertical and horizontal load are 250 g and 12 g, respectively. This work shows that the improved bionic piezoelectric actuator is feasible for eliminating backward motion and has a great working ability.
基金Humanities and Social Sciences Research Project of China’s Ministry of Education(23YJCZH242)Major Humanities and Social Sciences Research Projects in Zhejiang Higher Education Institutions(2024QN069)Hangzhou Collaborative Innovation Institute of Language Services,Hangzhou City University,China。
文摘This article centers on The Call of the Wild,an English novel by American author Jack London,alongside two Chinese translations by Dajie Liu and Menglin Zhang,and Rongyue Liu.Seventy sentences containing motion events and their corresponding translations were randomly selected for analysis.The study focuses on the primary elements of motion events-manner,path,and ground-and examines their Chinese translations through the lens of Skopos theory.Skopos theory emphasizes whether translators can adopt appropriate translation strategies according to various contextual factors during the translation process.Compared to verb-framed languages,satellite-framed languages possess a richer vocabulary for manner verbs,express more detailed manner information,use more satellite words to indicate paths,and incorporate more background information.Verb-framed languages,by contrast,typically express manner information only when necessary and tend to include less background information.The analysis reveals that both Chinese translations embody the core principle of Skopos theory:translation strategies are determined by their purpose.To fulfill the novel’s translation objectives,the translators adeptly adjust their strategies for motion event components based on different contextual needs.It is noted that the Chinese translations do not fully retain the characteristics of English as a typical satellite-framed language.This observation aligns with Skopos theory’s purpose-oriented approach,which prioritizes translation goals over strict adherence to source text characteristics.
基金Open Access funding enabled and organized by CAUL and its Member Institutions。
文摘Shape memory alloy(SMA)bars are currently preferred over elastomeric seismic isolators due to the elimination of degradation within effective damping and stiffness factors during the cyclic response of an isolation system.These bars could also be used to prevent the functionality of the isolator units from failing due to large deformations.This study aims to investigate the performance of a high damping rubber bearing(HDRB)isolator that is combined with two different types of SMA bars,i.e.,Nickel-Titanium(Ni-Ti)and Copper-Aluminum-Beryllium(Cu-Al-Be),subjected to near-fault ground motions that are characterized with forward directivity and fling step effects.To achieve this objective,a self-centering material with flag-shape,force-deformation hysteresis was utilized to simulate the behavior of SMA bars in OpenSees.A single degree of freedom(SDOF)system representing an isolated one-story shear building was developed to conduct nonlinear analysis under selected ground motions.The SMA bars were introduced as an X-shape within the model and were connected diagonally to the top and bottom of the isolator.Results showed that the HDRB system’s hysteretic response under near-fault ground accelerations experiences significant degradation,especially when near-fault motions involve the fling step effect.It was demonstrated that SMA bars effectively reduce large displacement observed in HDRB systems under near-fault earthquakes.Comparing the results of the base-isolated HDRB and SMA-HDRB subjected to selected ground motions demonstrated that maximum displacement was found to be significantly reduced by an average of 79%when SMA bars were used.Incorporating SMA bars with a larger diameter significantly improves the efficiency of SMA HDRB systems,and a reduction in maximum displacements is more pronounced for fling step,near-fault ground motions.
基金supported by National Science Foundation Grant No.2123824.
文摘Microrobots powered by an external magnetic field could be used for sophisticated medical applications such as cell treatment,micromanipulation,and noninvasive surgery inside the body.Untethered microrobot applications can benefit from haptic technology and telecommunication,enabling telemedical micro-manipulation.Users can manipulate the microrobots with haptic feedback by interacting with the robot operating system remotely in such applications.Artificially created haptic forces based on wirelessly transmitted data and model-based guidance can aid human operators with haptic sensations while manipulating microrobots.The system presented here includes a haptic device and a magnetic tweezer system linked together using a network-based teleoperation method with motion models in fluids.The magnetic microrobots can be controlled remotely,and the haptic interactions with the remote environment can be felt in real time.A time-domain passivity controller is applied to overcome network delay and ensure stability of communication.This study develops and tests a motion model for microrobots and evaluates two image-based 3D tracking algorithms to improve tracking accuracy in various Newtonian fluids.Additionally,it demonstrates that microrobots can group together to transport multiple larger objects,move through microfluidic channels for detailed tasks,and use a novel method for disassembly,greatly expanding their range of use in microscale operations.Remote medical treatment in multiple locations,remote delivery of medication without the need for physical penetration of the skin,and remotely controlled cell manipulations are some of the possible uses of the proposed technology.
基金funded by the Natural Science Basis Research Plan in Shaanxi Province of China(Program No.2023-JC-QN-0659)General Specialized Scientific Research Program of the Shaanxi Provincial Department of Education(Program 23JK0349).
文摘Legged robots have always been a focal point of research for scholars domestically and internationally.Compared to other types of robots,quadruped robots exhibit superior balance and stability,enabling them to adapt effectively to diverse environments and traverse rugged terrains.This makes them well-suited for applications such as search and rescue,exploration,and transportation,with strong environmental adaptability,high flexibility,and broad application prospects.This paper discusses the current state of research on quadruped robots in terms of development status,gait trajectory planning methods,motion control strategies,reinforcement learning applications,and control algorithm integration.It highlights advancements in modeling,optimization,control,and data-driven approaches.The study identifies the adoption of efficient gait planning algorithms,the integration of reinforcement learning-based control technologies,and data-driven methods as key directions for the development of quadruped robots.The aim is to provide theoretical references for researchers in the field of quadruped robotics.
基金supported by the National Natural Science Foundation of Jiangsu Province,China(Grant No.BK20231255).
文摘On the basis of the model tests,this paper explores the coupled hydrodynamic performance of the moonpool and the hull.This study aims to compare and analyze the variation in the hull heave response between the piston resonance state of the moonpool under wave excitation and the non-resonance state of the moonpool under wave-current excitation.A novel damping device specifically designed and fabricated for stepped moonpools has been developed.Before and after the installation of the damping device,the free surface response characteristics of the moonpool and heave motion response characteristics of the hull are compared.The findings show a clear correlation between the current speed and heave response characteristics of the hull.During the seakeeping design phase of the drilling vessel,the current speed is an additional critical factor that cannot be disregarded,alongside the moonpool effect.A correlation exists between the fluid dynamics occurring within the moonpool and the heave motion of the vessel hull.A reduction in the amplitude of the motion of the moonpool water results in a decrease in the heave motion of the hull.This study provides a reference for alleviating the seakeeping of a drill ship’s heave response and enhancing the safety and efficiency of the operation.
基金supported by the National Natural Science Foundation ofChina(GrantNo.12402291)the Beijing Natural Science Foundation(No.3244043)the Research Start-up Funds of Hangzhou International Innovation Institute of Beihang University(Grant Nos.2024KQ008,2024KQ062).
文摘This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation frequencies.Results reveal that the eigenfrequencies vary spatially due to distinct oscillation modes occurring at different droplet locations.Notably,the fundamental eigenfrequency decreases with reducing droplet volume,while droplet viscosity exerts minimal influence on this frequency.Prior to the onset of motion,the dynamic contact angle consistently remains between the advancing and receding angles.The inertial forces generated by droplet oscillation are found to be significantly greater than the adhesion forces,indicating that classical static models are inadequate for capturing inertial contributions to droplet motion.These findings offer new insights into the role of oscillatory behavior in influencing the dynamics of droplet motion,and contribute to a more detailed understanding of wind-driven droplet transport phenomena.
基金Supported by Shanxi Provincial Natural Science Foundation(Grant No.2021JM010)The Youth Innovation Team of Shaanxi Universities.
文摘This study aimed to identify and compensate for the geometric errors of the double swiveling axes in a five-axis computer numerical control(CNC)machining center.Hence,a three-dimensional coordinate calculation algorithm for a measured point with additional rotational rigid body motion constraints is proposed.The motion constraints of the rotational rigid body were analyzed,and a mathematical model of the measured point algorithm in the swiveling axes was established.The Levenberg-Marquard method was used to solve the nonlinear superstatically determined equations.The spatial coordinate error was used to separate the spatial deviation of the measured point.An identification model of the position-independent and position-dependent geometric errors was established.The three-dimensional coordinate-solving algorithm of the measured point in the swiveling axis and geometric error identification method based on the Monte Carlo method were analyzed numerically.Geometric error measurement and cutting experiments were performed on a VMC25100U five-axis machining center,which integrated two swiveling axes.Geometric errors of the A-and B-axes were identified and measured experimentally.The angular positioning errors before and after compensation were measured using a laser interferometer,which verified the effectiveness of the proposed algorithm.A cutting experiment of a round table part was performed.The shape and position accuracy of the processed part before and after compensation were detected using a coordinate measuring machine.It verified that the geometric error of the swiveling axis was effectively compensated by the algorithm proposed herein.
基金supported by the National Natural Science Foundation of China(No.52293471)National Key R&D Program of China(No.2022YFB3707303).
文摘The flocculation behavior of carbon black (CB)-filled isoprene rubber (IR) nanocomposites was systematically investigated under both dynamic and static conditions to unravel the distinct mechanisms governing filler network evolution.Under dynamic conditions,small oscillatory shear strains (0.1%) significantly enhanced filler particle motion,leading to pronounced agglomeration and a flocculation degree of about 4.3MPa at 145℃.In contrast,static flocculation exhibited a fundamentally different mechanism dominated by polymer chain dynamics,which is driven mainly by thermal activation.Radial distribution function (RDF) analysis of transmission electron microscopy (TEM) images revealed a slight decrease (2 nm) in the interparticle distance peak after static annealing at 100℃ for 7 h,indicating localized motion of CB particles.However,the overall filler network remained stable,with no significant agglomeration observed.The increase in bound rubber content from about 23% to 28% with rising temperature further confirmed the dominant role of polymer chain adsorption and interfacial reinforcement in static flocculation.These findings highlight the critical influence of external strain on filler network formation and provide new insights into the polymer-dominated mechanism of static flocculation.The results offer practical guidance for optimizing the storage and processing of rubber nanocomposites,particularly in applications where static flocculation during prolonged storage is a concern.
