The dynamic dexterity is an important issue for manipulator design, some indices were proposed for analyzing dynamic dexterity, but they can evaluate the dynamic performance just at one pose in the workspaee of the ma...The dynamic dexterity is an important issue for manipulator design, some indices were proposed for analyzing dynamic dexterity, but they can evaluate the dynamic performance just at one pose in the workspaee of the manipulator, and can＇t be applied to dynamic design expediently. Much work has been done in the kinematic optimization, but the work in the dynamic optimization is much less. A global dynamic condition number index is proposed and applied to the dynamic optimization design the parallel manipulator. This paper deals with the dynamic manipulability and dynamic optimization of a two degree-of-freedom （DOF） parallel manipulator. The particular velocity and particular angular velocity matrices of each moving part about the part＇s pivot point are derived fi＇om the kinematic formulation of the manipulator, and the inertial force and inertial movement are obtained utilizing Newton-Euler formulation, then the inverse dynamic model of the parallel manipulator is proposed based on the virtual work principle. The general inertial ellipsoid and dynamic manipulability ellipsoid are applied to evaluate the dynamic performance of the manipulator, a global dynamic condition number index based on the condition number of general inertial matrix in the workspace is proposed, and then the link lengths of the manipulator is redesigned to optimize the dynamic manipulability by this index. The dynamic manipulability of the origin mechanism and the optimized mechanism are compared, the result shows that the optimized one is much better. The global dynamic condition number index has good effect in evaluating the dynamic dexterity of the whole workspace, and is efficient in the dynamic optimal design of the parallel manipulator.展开更多
Microrobots play an essential role in early diagnosis and precision medicine with the increasing demands for controllability in bio-medicine and micromanipulation,which can complete the pre-designed behavior under ext...Microrobots play an essential role in early diagnosis and precision medicine with the increasing demands for controllability in bio-medicine and micromanipulation,which can complete the pre-designed behavior under external stimulation.However,most microrobots are currently made of a single material system and focus on fabricating a driving module as the main structure of microrobots.This hinders the integration of diverse functions in one microrobot to fulfill the complex application.Here,a multi-material and multi-module hand-microrobot based on femtosecond laser direct writing technology is proposed,which has a pH-responsive capturing module and a magnetic-responsive transportation module(MRTM).This microrobot can not only respond to pH for capturing and releasing objects,but also respond to magnetic fields for cargo delivery even with obstacles.The two responding modules of the hand-microrobot are fabricated independently,and can collaborate with each other to achieve the delivery of target objects like polystyrene(PS)microsphere(10µm)or 786-O cell by capturing,transporting,and spatial rolling.Besides,the MRTM can be locally fabricated on any prefabricated static structure,so that the whole microrobot can achieve controllable motion.This strategy is expected to be used to manipulate cells,deliver drugs for precise treatment,and environmental treatment.展开更多
Professor Zhan Hongsheng(詹红生),as the national representative inheritor of Shanghai Shi’s Orthopedics and Traumatology,has led his team in long-term dedication to the research of Chinese spinal manipulative medicin...Professor Zhan Hongsheng(詹红生),as the national representative inheritor of Shanghai Shi’s Orthopedics and Traumatology,has led his team in long-term dedication to the research of Chinese spinal manipulative medicine.He has achieved outstanding accomplishments in areas such as school inheritance,theoretical construction,technological innovation,standard establishment,scientific research translation,and talent cultivation,thereby advancing the modernization,standardization,and internationalization of Chinese spinal manipulative medicine.展开更多
Single-cell biomechanics and electrophysiology measuring tools have transformed biological research over the last few decades,which enabling a comprehensive and nuanced understanding of cellular behavior and function....Single-cell biomechanics and electrophysiology measuring tools have transformed biological research over the last few decades,which enabling a comprehensive and nuanced understanding of cellular behavior and function.Despite their high-quality information content,these single-cell measuring techniques suffer from laborious manual processing by highly skilled workers and extremely low throughput(tens of cells per day).Recently,numerous researchers have automated the measurement of cell mechanical and electrical signals through robotic localization and control processes.While these efforts have demonstrated promising progress,critical challenges persist,including human dependency,learning complexity,in-situ measurement,and multidimensional signal acquisition.To identify key limitations and highlight emerging opportunities for innovation,in this review,we comprehensively summarize the key steps of robotic technologies in single-cell biomechanics and electrophysiology.We also discussed the prospects and challenges of robotics and automation in biological research.By bridging gaps between engineering,biology,and data science,this work aims to stimulate interdisciplinary research and accelerate the translation of robotic single-cell technologies into practical applications in the life sciences and medical fields.展开更多
Smart windows that can repel diverse liquids are highly attractive for the development of self-cleaning building system.Despite immense achievements having been made in drophobic smart windows,unfortunately,the limita...Smart windows that can repel diverse liquids are highly attractive for the development of self-cleaning building system.Despite immense achievements having been made in drophobic smart windows,unfortunately,the limitations of inferior transparency,unsatisfactory flexibility,and scarce functionality greatly hinder their practical applications.Here,a multifunctional,all-flexible and slef-cleaning electrothermal-actuated(SETA)module with superior transparency is developed by sandwiching the hydrophobic SiO_(2) nanoparticles decorated silver nanowires thin-film heater and the thermo-responsive hydrogel.Through loading/discharging an electric stimulus of 5 V,the optical visibility of SETA could be in situ switched between an opaque state(T_(550)=11.0%)and a transparent state(T_(550)=84.9%)relying on the dynamically collapsed and swollen transition of hydrogel on planar and three-dimensional curved surfaces.Moreover,SETA chipset is able to repel diverse liquids,including organic and inorganic species,showcasing an excellent self-cleaning capability.Lastly,all-in-one multifunctionalities,including pixelated display,thermal regulation,defogging,and self-cleaning on a single SETA chipset,are successfully deployed.Compared to the previous windows,the current SETA chipset is more competent for optical switching in reality,owing to its portable,energy-efficient,flexible,highly-transparent,and on-demand manipulating advantages.This work provides inspirations for self-cleaning greenhouse,tunable optics,intelligent vehicles,and so on.展开更多
Vortex-induced vibration(VIV)of an underwater manipulator in pulsating flow presents a notable engineering problem in precise control due to the velocity variation in the flow.This study investigates the VIV response ...Vortex-induced vibration(VIV)of an underwater manipulator in pulsating flow presents a notable engineering problem in precise control due to the velocity variation in the flow.This study investigates the VIV response of an underwater manipulator subjected to pulsating flow,focusing on how different postures affect the behavior of the system.The effects of pulsating parameters and manipulator arrangement on the hydrodynamic coefficient,vibration response,motion trajectory,and vortex shedding behaviors were analyzed.Results indicated that the cross flow vibration displacement in pulsating flow increased by 32.14%compared to uniform flow,inducing a shift in the motion trajectory from a crescent shape to a sideward vase shape.In the absence of interference between the upper and lower arms,the lift coefficient of the manipulator substantially increased with rising pulsating frequency,reaching a maximum increment of 67.0%.This increase in the lift coefficient led to a 67.05%rise in the vibration frequency of the manipulator in the in-line direction.As the pulsating amplitude increased,the drag coefficient of the underwater manipulator rose by 36.79%,but the vibration frequency in the cross-flow direction decreased by 56.26%.Additionally,when the upper and lower arms remained in a state of mutual interference,the cross-flow vibration amplitudes of the upper and lower arms were approximately 1.84 and 4.82 times higher in a circular-elliptical arrangement compared to an elliptical-circular arrangement,respectively.Consequently,the flow field shifted from a P+S pattern to a disordered pattern,disrupting the regularity of the motion trajectory.展开更多
Soft robotic manipulators represent a rapidly evolving field characterized by inherent compliance,adaptability,and safe interactions within unstructured environments.Over the past decade(2015-2025),significant advance...Soft robotic manipulators represent a rapidly evolving field characterized by inherent compliance,adaptability,and safe interactions within unstructured environments.Over the past decade(2015-2025),significant advancements have trans-formed their capabilities through novel designs inspired by biological systems,advanced modeling frameworks,sophisti-cated control strategies,and integration into diverse real-world applications.Recent innovations in multifunctional mate-rials and emerging actuation technologies have markedly expanded manipulator performance,reliability,and dexterity.Concurrently,developments in modeling have progressed from simplified geometric methods toward highly accurate physics-based and hybrid data-driven approaches,substantially improving real-time prediction and controllability.Coupled with these developments,adaptive and robust control strategies-including learning-based techniques-have enabled unprec-edented autonomy and precision in challenging application domains such as Minimally Invasive Surgery(MIS),precision agriculture,deep-sea exploration,disaster recovery,and space missions.Despite these remarkable strides,key challenges remain,notably regarding scalability,long-term material durability,robust integrated sensing,and standardized evaluation procedures.This review comprehensively synthesizes recent advances,critically evaluates state-of-the-art methodologies,and systematically identifies existing gaps to provide a clear roadmap and targeted research directions,guiding future developments toward the broader adoption and optimal utilization of soft robotic manipulators.展开更多
Droplet-based microfluidics have drawn much attention in recent years and have been successfully applied in biochemical analysis,material synthesis,and biomedical engineering.Precise and flexible manipulations of drop...Droplet-based microfluidics have drawn much attention in recent years and have been successfully applied in biochemical analysis,material synthesis,and biomedical engineering.Precise and flexible manipulations of droplets are the basis of various applications.Numerous techniques have been introduced to achieve on-demand control of droplets,including electric,magnetic,acoustic,optical,and thermal methods.Among these,the combination of acoustics and microfluidics(termed acoustofluidics)has shown great potential and advantages in droplet manipulation as it is non-invasive,high-precision,low-cost,easily integrated,and biocompatible.Here,we summarize recent works on acoustofluidic manipulations of droplet-based microfluidics.This paper is structured into three main sections.First,the commonly used acoustic devices in acoustofluidics and their working principles are introduced.Such acoustic devices include interdigital transducers,Lamb wave resonators,and bulk acoustic resonators,and generate acoustic waves with frequencies ranging from kilohertz to gigahertz.Second,the forces and effects involved in droplet manipulations using acoustofluidics are analyzed.Third,the manipulation processes of droplet microfluidics using various acoustofluidic techniques are summarized and compared with other methods,including droplet generation,mixing,splitting,fusion,sorting,transportation,and internal particle patterning.Finally,current challenges and future prospects for acoustofluidic manipulation techniques for droplet-based microfluidics are discussed.展开更多
The safe driving and operation of trains is a necessary condition for ensuring the safe operation of trains.In particular,heavy-haul trains are characterized by the difficulty in driving and operation.Considering the ...The safe driving and operation of trains is a necessary condition for ensuring the safe operation of trains.In particular,heavy-haul trains are characterized by the difficulty in driving and operation.Considering the uncertainties in train driving and operation,this paper analyzes the relationship between the safety of heavy-haul electric locomotive hauled trains and driving and operation.It studies the auxiliary intelligent driving safety operation control methods.Through K-means to identify the characteristics of drivers'driving manipulation,the hidden Markov model adaptively adjusts the train driving and operation sequence,and conducts auxiliary driving reconstruction for heavy-haul locomotive driving and operation.Based on the train running curve and the locomotive traction/braking characteristics,it smoothly controls the exertion of the traction/braking force of heavy-haul locomotives,thereby optimizing the driving safety control of heavy-haul trains in the vehicle-environment-track system.Finally,the train operation simulation and optimized driving verification are carried out by simulating some track sections.The results show that the proposed method can correct and pre-optimize driving operations,improving the smoothness of heavy-haul trains by approximately 10%.It verifies the effectiveness of the proposed train assisted driving control reconstruction method,facilitating the smooth and safe operation of heavy-haul trains.展开更多
Octopuses,due to their flexible arms,marvelous adaptability,and powerful suckers,are able to effortlessly grasp and disengage various objects in the marine surrounding without causing devastation.However,manipulating ...Octopuses,due to their flexible arms,marvelous adaptability,and powerful suckers,are able to effortlessly grasp and disengage various objects in the marine surrounding without causing devastation.However,manipulating delicate objects such as soft and fragile foods underwater require gentle contact and stable adhesion,which poses a serious challenge to now available soft grippers.Inspired by the sucker infundibulum structure and flexible tentacles of octopus,herein we developed a hydraulically actuated hydrogel soft gripper with adaptive maneuverability by coupling multiple hydrogen bond-mediated supramolecular hydrogels and vat polymerization three-dimensional printing,in which hydrogel bionic sucker is composed of a tunable curvature membrane,a negative pressure cavity,and a pneumatic chamber.The design of the sucker structure with the alterable curvature membrane is conducive to realize the reliable and gentle switchable adhesion of the hydrogel soft gripper.As a proof-of-concept,the adaptive hydrogel soft gripper is capable of implement diversified underwater tasks,including gingerly grasping fragile foods like egg yolks and tofu,as well as underwater robots and vehicles that station-keeping and crawling based on switchable adhesion.This study therefore provides a transformative strategy for the design of novel soft grippers that will render promising utilities for underwater exploration soft robotics.展开更多
Trajectory tracking for nonlinear robotic systems remains a fundamental yet challenging problem in control engineering,particularly when both precision and efficiency must be ensured.Conventional control methods are o...Trajectory tracking for nonlinear robotic systems remains a fundamental yet challenging problem in control engineering,particularly when both precision and efficiency must be ensured.Conventional control methods are often effective for stabilization but may not directly optimize long-term performance.To address this limitation,this study develops an integrated framework that combines optimal control principles with reinforcement learning for a single-link robotic manipulator.The proposed scheme adopts an actor–critic structure,where the critic network approximates the value function associated with the Hamilton–Jacobi–Bellman equation,and the actor network generates near-optimal control signals in real time.This dual adaptation enables the controller to refine its policy online without explicit system knowledge.Stability of the closed-loop system is analyzed through Lyapunov theory,ensuring boundedness of the tracking error.Numerical simulations on the single-link manipulator demonstrate that themethod achieves accurate trajectory followingwhile maintaining lowcontrol effort.The results further showthat the actor–critic learning mechanism accelerates convergence of the control policy compared with conventional optimization-based strategies.This work highlights the potential of reinforcement learning integrated with optimal control for robotic manipulators and provides a foundation for future extensions to more complex multi-degree-of-freedom systems.The proposed controller is further validated in a physics-based virtual Gazebo environment,demonstrating stable adaptation and real-time feasibility.展开更多
Military image encryption plays a vital role in ensuring the secure transmission of sensitive visual information from unauthorized access.This paper proposes a new Tri-independent keying method for encrypting military...Military image encryption plays a vital role in ensuring the secure transmission of sensitive visual information from unauthorized access.This paper proposes a new Tri-independent keying method for encrypting military images.The proposed encryption method is based on multilevel security stages of pixel-level scrambling,bitlevel manipulation,and block-level shuffling operations.For having a vast key space,the input password is hashed by the Secure Hash Algorithm 256-bit(SHA-256)for generating independently deterministic keys used in the multilevel stages.A piecewise pixel-level scrambling function is introduced to perform a dual flipping process controlled with an adaptive key for obscuring the spatial relationships between the adjacent pixels.Adynamicmasking scheme is presented for conducting a bit-level manipulation based on distinct keys that change over image regions,providing completely different encryption results on identical regions.To handle the global correlation between large-scale patterns,a chaotic index-map system is employed for shuffling image regions randomly across the image domain based on a logistic map seeded with a private key.Experimental results on a dataset of military images show the effectiveness of the proposed encryption method in producing excellent quantitative and qualitative results.The proposed method obtains uniform histogram distributions,high entropy values around the ideal(≈8 bits),Number of Pixel Change Rate(NPCR)values above 99.5%,and low Peak Signal-to-Noise Ratio(PSNR)over all encrypted images.This validates the robustness of the proposed method against cryptanalytic attacks,verifying its ability to serve as a practical basis for secure image transmission in defense systems.展开更多
Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to smal...Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to small particles within the dipole regime or specific light fields,thereby lacking universality and sometimes leading to ambiguity.To overcome these limitations,we establish a fully analytical and comprehensive framework for optical force/torque based on the Cartesian multipole expansion theory,which is applicable to arbitrary-sized bi-isotropic(chiral)spherical particles immersed in arbitrary monochromatic optical fields.Rigorous expressions are thus derived,which explicitly bridge the optical force/torque with particle-propertydependent coefficients and“force/torque source”quantities characterizing the incident light structures.Such quantities identify the ultimate physical origins of optical force/torque and are systematically classified into four categories based on their parity(P)and duality(D)symmetries.Each category interacts selectively with particles exhibiting specific P and D(a)symmetries,thus inducing distinct optical forces or torques with characteristic physical behaviors.This classification establishes the mutual symmetry-breaking criteria necessary for both particles and light beams to generate optical force/torque,offering a physics-based roadmap for engineering optical manipulations such as chirality sorting,light-driven micromotors,and beyond.展开更多
Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on ...Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on energy storage and conversion applications,such as use as anodes in lithium-ion batteries.In this paper,all-inorganic lead-free halide perovskite Cs_(3)Bi_(2)Cl_(9)powders were synthesized by the grinding method,and the lattice was successfully adjusted via introducing Mn^(2+).The characterization results show that Mn-ion substitution can cause local lattice distortion to restructure the lattice,which will cause a mixed arrangement of[BiCl_(6)]octahedra to improve the performance of the anode material.This new material can provide a feasible solution for solving the problem of low specific capacity anode materials caused by unstable crystal structures,and also indicates that such perovskites with unique crystal structures and lattice tunability have broad application prospects in lithium-ion batteries.展开更多
In-space cable-driven manipulators exhibit several advantages,such as a large range of motion,high dexterity,and lightweight structure.However,kinematic and dynamic analysis play an essential role in designing a cable...In-space cable-driven manipulators exhibit several advantages,such as a large range of motion,high dexterity,and lightweight structure.However,kinematic and dynamic analysis play an essential role in designing a cable-driven manipulator.In this paper,the kinematic analysis of a type of cable-driven manipulator is performed,and a motion planning scheme is conducted to actuate this manipulator.Moreover,a flexible multi-body dynamic model of a cable-driven manipulator considering the frictional contact between the cables and pulleys is established.To describe properties such as flexibility,vibration,and variable length of the cable,this paper utilizes reducedorder beam elements of the Absolute Nodal Coordinates Formulation(ANCF)in Arbitrary Lagrangian Eulerian(ALE)framework.Additionally,a virtual element is introduced to model the contact segment in the cable-pulley system.A tension decay factor is employed to account for the friction in the contact segment.To validate the proposed method,a semi-analytical model based on D'Alembert's principle is established.Cross-verification is performed to validate the accuracy of both models.The model is further applied to simulate the rotation of the cable-driven manipulator with different structural parameters and frictional factors.The results from the analyses provide valuable guidance for the design and motion control of the in-space cable-driven manipulator.Finally,a prototype of a single module is manufactured and tested.Ground experiments are carried out to verify the kinematic and dynamic models.展开更多
To address the finite-time tracking control problem for fractional-order nonlinear systems(FONSs) with actuator faults and external disturbance,a novel strategy of the finite-time adaptive fuzzy fault-tolerant control...To address the finite-time tracking control problem for fractional-order nonlinear systems(FONSs) with actuator faults and external disturbance,a novel strategy of the finite-time adaptive fuzzy fault-tolerant controller is presented in this paper by utilizing the finite-time stability theory and fractional-order dynamic surface control scheme combined with backstepping method.A new lemma is developed for analyzing the finite-time stability of FONSs in terms of fractional differential inequality,which modifies some existing results.Fuzzy logic systems are adopted to identify unknown nonlinear characteristics in FONS.In order to compensate for the influence of unknown external disturbance and estimation error for fuzzy logic systems,an auxiliary function is employed to estimate the upper bound of parameters online.Furthermore,a global coordinate transformation is first introduced initially to decouple the fractional-order dynamic system of a specific class of underactuated single-link flexible manipulator systems,thereby transforming it into lower triangular systems.Simulation analyses and experimental results verify the feasibility and effectiveness of finite-time tracking control algorithm.展开更多
The kagome ferrimagnet TbMn_(6)Sn_(6),featuring a pristine Mn kagome lattice,has emerged as a candidate Chern magnet with a large intrinsic anomalous Hall effect(AHE).While chemical substitution can modulate its prope...The kagome ferrimagnet TbMn_(6)Sn_(6),featuring a pristine Mn kagome lattice,has emerged as a candidate Chern magnet with a large intrinsic anomalous Hall effect(AHE).While chemical substitution can modulate its properties,hydrostatic pressure provides a disorder-free route to manipulate electronic and magnetic interactions.Herein,we investigate the effects of hydrostatic pressure on electrical and magneto-transport in TbMn6Sn6 up to 18.3 GPa.Pressure significantly enhances hysteresis in the magnetoresistance and Hall responses,causing a concurrent monotonic coercive field increase,suggesting the enhancement of interlayer magnetic couplings in a robust c-axis ferrimagnetic order.The intrinsic anomalous Hall conductivity increases considerably from 129.5 S·cm^(−1) at ambient pressure conditions to 448.7 S·cm^(−1) at 14.0 GPa—an enhancement of 247%that is unprecedented among pressure-tuned kagome magnets.Based on density functional theory calculations,we reveal that pressure induces multiple gap openings near the Fermi level,giving rise to pronounced Berry curvature hotspots that may contribute to the AHE.Our results show that pressure can be used to enhance the intrinsic topological responses of this kagome magnet.展开更多
Plasma-based optical elements can withstand laser intensities several orders of magnitude higher than traditional optical elements,making them highly promising for manipulating relativistic intensity laser pulses.In t...Plasma-based optical elements can withstand laser intensities several orders of magnitude higher than traditional optical elements,making them highly promising for manipulating relativistic intensity laser pulses.In this work,we propose and demonstrate a novel microstructured plasma target,inspired by the design of traditional Fresnel zone plates.The specific target structure causes diffraction of the input laser at each zone,resulting in constructive interference and facilitating effective focusing of the input laser pulse.Three-dimensional particle-in-cell simulation results show that the microstructured plasma target can focus Gaussian laser pulses with an intensity of the order of 10^(22) W/cm^(2)to an intensity exceeding 10^(24) W/cm^(2)with the laser focus spot size approaching the diffraction limit of-0.73μm and laser fluence enhancement by a factor of 46.It is also found that when the microstructured plasma target is modified into a reflective element,laser intensities up to 10^(25) W/cm^(2)may be achieved.This extremely high-intensity tightly focused laser pulse can trigger intense photon radiation when interacting with targets,(e.g.,wire plasma targets),with potential applications in laboratory astrophysics,as well as providing the opportunity to explore phenomena such as vacuum birefringence and quantum electrodynamical cascades.展开更多
The integration of acoustic vortices with chiral exceptional points (CEPs) in ring cavities enables the controlled unidirectional coupling and manipulation of orbital angular momentum (OAM) modes. However, realizing m...The integration of acoustic vortices with chiral exceptional points (CEPs) in ring cavities enables the controlled unidirectional coupling and manipulation of orbital angular momentum (OAM) modes. However, realizing multiple vortex orders within a single cavity remains challenging because non-Hermitian modulations must be tailored for different OAM modes simultaneously. We propose a simple approach for constructing multiple CEPs by arranging resistive and reactive impedance-boundary modulations with specific azimuthal patterns along the inner wall of an acoustic ring cavity. This design allows for independent engineering of multiple OAM eigenmodes and their simultaneous excitation using a single monopole source. As a representative example, we demonstrate first-, second-, and third-order OAM generation in both an exact PT-symmetric cavity with balanced gain and loss and a loss-biased passive counterpart that offers additional chirality control through the chirality-reversal effect. This study provides a flexible and compact framework for generating and manipulating multi-order acoustic OAM modes on non-Hermitian platforms.展开更多
Robots are key to expanding the scope of space applications.The end-to-end training for robot vision-based detection and precision operations is challenging owing to constraints such as extreme environments and high c...Robots are key to expanding the scope of space applications.The end-to-end training for robot vision-based detection and precision operations is challenging owing to constraints such as extreme environments and high computational overhead.This study proposes a lightweight integrated framework for grasp detection and imitation learning,named GD-IL;it comprises a grasp detection algorithm based on manipulability and Gaussian mixture model(manipulability-GMM),and a grasp trajectory generation algorithm based on a two-stage robot imitation learning algorithm(TS-RIL).In the manipulability-GMM algorithm,we apply GMM clustering and ellipse regression to the object point cloud,propose two judgment criteria to generate multiple candidate grasp bounding boxes for the robot,and use manipulability as a metric for selecting the optimal grasp bounding box.The stages of the TS-RIL algorithm are grasp trajectory learning and robot pose optimization.In the first stage,the robot grasp trajectory is characterized using a second-order dynamic movement primitive model and Gaussian mixture regression(GMM).By adjusting the function form of the forcing term,the robot closely approximates the target-grasping trajectory.In the second stage,a robot pose optimization model is built based on the derived pose error formula and manipulability metric.This model allows the robot to adjust its configuration in real time while grasping,thereby effectively avoiding singularities.Finally,an algorithm verification platform is developed based on a Robot Operating System and a series of comparative experiments are conducted in real-world scenarios.The experimental results demonstrate that GD-IL significantly improves the effectiveness and robustness of grasp detection and trajectory imitation learning,outperforming existing state-of-the-art methods in execution efficiency,manipulability,and success rate.展开更多
基金supported by National Natural Science Foundation of China (Grant No. 50605041, No. 50775125)National Basic Research Program of China (973 Program, Grant No. 2006CB705400)
文摘The dynamic dexterity is an important issue for manipulator design, some indices were proposed for analyzing dynamic dexterity, but they can evaluate the dynamic performance just at one pose in the workspaee of the manipulator, and can＇t be applied to dynamic design expediently. Much work has been done in the kinematic optimization, but the work in the dynamic optimization is much less. A global dynamic condition number index is proposed and applied to the dynamic optimization design the parallel manipulator. This paper deals with the dynamic manipulability and dynamic optimization of a two degree-of-freedom （DOF） parallel manipulator. The particular velocity and particular angular velocity matrices of each moving part about the part＇s pivot point are derived fi＇om the kinematic formulation of the manipulator, and the inertial force and inertial movement are obtained utilizing Newton-Euler formulation, then the inverse dynamic model of the parallel manipulator is proposed based on the virtual work principle. The general inertial ellipsoid and dynamic manipulability ellipsoid are applied to evaluate the dynamic performance of the manipulator, a global dynamic condition number index based on the condition number of general inertial matrix in the workspace is proposed, and then the link lengths of the manipulator is redesigned to optimize the dynamic manipulability by this index. The dynamic manipulability of the origin mechanism and the optimized mechanism are compared, the result shows that the optimized one is much better. The global dynamic condition number index has good effect in evaluating the dynamic dexterity of the whole workspace, and is efficient in the dynamic optimal design of the parallel manipulator.
基金financial support of the National Key R&D Program of China(Grant Nos.2024YFB4607402 and 2016YFA0200500)National Natural Science Foundation of China(NSFC,Grant Nos.61975213,61475164 and 61205194)International Partnership Program of Chinese Academy of Sciences(GJHZ2021130)。
文摘Microrobots play an essential role in early diagnosis and precision medicine with the increasing demands for controllability in bio-medicine and micromanipulation,which can complete the pre-designed behavior under external stimulation.However,most microrobots are currently made of a single material system and focus on fabricating a driving module as the main structure of microrobots.This hinders the integration of diverse functions in one microrobot to fulfill the complex application.Here,a multi-material and multi-module hand-microrobot based on femtosecond laser direct writing technology is proposed,which has a pH-responsive capturing module and a magnetic-responsive transportation module(MRTM).This microrobot can not only respond to pH for capturing and releasing objects,but also respond to magnetic fields for cargo delivery even with obstacles.The two responding modules of the hand-microrobot are fabricated independently,and can collaborate with each other to achieve the delivery of target objects like polystyrene(PS)microsphere(10µm)or 786-O cell by capturing,transporting,and spatial rolling.Besides,the MRTM can be locally fabricated on any prefabricated static structure,so that the whole microrobot can achieve controllable motion.This strategy is expected to be used to manipulate cells,deliver drugs for precise treatment,and environmental treatment.
文摘Professor Zhan Hongsheng(詹红生),as the national representative inheritor of Shanghai Shi’s Orthopedics and Traumatology,has led his team in long-term dedication to the research of Chinese spinal manipulative medicine.He has achieved outstanding accomplishments in areas such as school inheritance,theoretical construction,technological innovation,standard establishment,scientific research translation,and talent cultivation,thereby advancing the modernization,standardization,and internationalization of Chinese spinal manipulative medicine.
基金the National Natural Science Foundation of China[62525301,62127811,62433019]the New Cornerstone Science Foundation through the XPLORER PRIZEthe financial support by the China Postdoctoral Science Foundation[GZB20240797].
文摘Single-cell biomechanics and electrophysiology measuring tools have transformed biological research over the last few decades,which enabling a comprehensive and nuanced understanding of cellular behavior and function.Despite their high-quality information content,these single-cell measuring techniques suffer from laborious manual processing by highly skilled workers and extremely low throughput(tens of cells per day).Recently,numerous researchers have automated the measurement of cell mechanical and electrical signals through robotic localization and control processes.While these efforts have demonstrated promising progress,critical challenges persist,including human dependency,learning complexity,in-situ measurement,and multidimensional signal acquisition.To identify key limitations and highlight emerging opportunities for innovation,in this review,we comprehensively summarize the key steps of robotic technologies in single-cell biomechanics and electrophysiology.We also discussed the prospects and challenges of robotics and automation in biological research.By bridging gaps between engineering,biology,and data science,this work aims to stimulate interdisciplinary research and accelerate the translation of robotic single-cell technologies into practical applications in the life sciences and medical fields.
基金supported by the National Key Research and Development Program of China(Grant No.2024YFB4610700)the Fundamental Research Funds for the Central Universities(Grant No.JZ2025HGTG0269)+4 种基金the National Natural Science Foundation of China(Grant Nos.52005475,62305321)the Natural Science Foundation of Anhui Province(Grant Nos.JZ2024AKZR0561,2308085QE167)Major Scientific and Technological Projects in Anhui Province(Grant No.202203a05020014)Opening Project of the Key Laboratory of Bionic Engineering(Ministry of Education)Jilin University(Grant No.K202204)。
文摘Smart windows that can repel diverse liquids are highly attractive for the development of self-cleaning building system.Despite immense achievements having been made in drophobic smart windows,unfortunately,the limitations of inferior transparency,unsatisfactory flexibility,and scarce functionality greatly hinder their practical applications.Here,a multifunctional,all-flexible and slef-cleaning electrothermal-actuated(SETA)module with superior transparency is developed by sandwiching the hydrophobic SiO_(2) nanoparticles decorated silver nanowires thin-film heater and the thermo-responsive hydrogel.Through loading/discharging an electric stimulus of 5 V,the optical visibility of SETA could be in situ switched between an opaque state(T_(550)=11.0%)and a transparent state(T_(550)=84.9%)relying on the dynamically collapsed and swollen transition of hydrogel on planar and three-dimensional curved surfaces.Moreover,SETA chipset is able to repel diverse liquids,including organic and inorganic species,showcasing an excellent self-cleaning capability.Lastly,all-in-one multifunctionalities,including pixelated display,thermal regulation,defogging,and self-cleaning on a single SETA chipset,are successfully deployed.Compared to the previous windows,the current SETA chipset is more competent for optical switching in reality,owing to its portable,energy-efficient,flexible,highly-transparent,and on-demand manipulating advantages.This work provides inspirations for self-cleaning greenhouse,tunable optics,intelligent vehicles,and so on.
基金Supported by the National Natural Science Foundation of China(No.51905211)A Project of the“20 Regulations for New Universities”Funding Program of Jinan(No.202228116).
文摘Vortex-induced vibration(VIV)of an underwater manipulator in pulsating flow presents a notable engineering problem in precise control due to the velocity variation in the flow.This study investigates the VIV response of an underwater manipulator subjected to pulsating flow,focusing on how different postures affect the behavior of the system.The effects of pulsating parameters and manipulator arrangement on the hydrodynamic coefficient,vibration response,motion trajectory,and vortex shedding behaviors were analyzed.Results indicated that the cross flow vibration displacement in pulsating flow increased by 32.14%compared to uniform flow,inducing a shift in the motion trajectory from a crescent shape to a sideward vase shape.In the absence of interference between the upper and lower arms,the lift coefficient of the manipulator substantially increased with rising pulsating frequency,reaching a maximum increment of 67.0%.This increase in the lift coefficient led to a 67.05%rise in the vibration frequency of the manipulator in the in-line direction.As the pulsating amplitude increased,the drag coefficient of the underwater manipulator rose by 36.79%,but the vibration frequency in the cross-flow direction decreased by 56.26%.Additionally,when the upper and lower arms remained in a state of mutual interference,the cross-flow vibration amplitudes of the upper and lower arms were approximately 1.84 and 4.82 times higher in a circular-elliptical arrangement compared to an elliptical-circular arrangement,respectively.Consequently,the flow field shifted from a P+S pattern to a disordered pattern,disrupting the regularity of the motion trajectory.
基金Open access funding provided by The Science,Technology&Innovation Funding Authority(STDF)in cooperation with The Egyptian Knowledge Bank(EKB).
文摘Soft robotic manipulators represent a rapidly evolving field characterized by inherent compliance,adaptability,and safe interactions within unstructured environments.Over the past decade(2015-2025),significant advancements have trans-formed their capabilities through novel designs inspired by biological systems,advanced modeling frameworks,sophisti-cated control strategies,and integration into diverse real-world applications.Recent innovations in multifunctional mate-rials and emerging actuation technologies have markedly expanded manipulator performance,reliability,and dexterity.Concurrently,developments in modeling have progressed from simplified geometric methods toward highly accurate physics-based and hybrid data-driven approaches,substantially improving real-time prediction and controllability.Coupled with these developments,adaptive and robust control strategies-including learning-based techniques-have enabled unprec-edented autonomy and precision in challenging application domains such as Minimally Invasive Surgery(MIS),precision agriculture,deep-sea exploration,disaster recovery,and space missions.Despite these remarkable strides,key challenges remain,notably regarding scalability,long-term material durability,robust integrated sensing,and standardized evaluation procedures.This review comprehensively synthesizes recent advances,critically evaluates state-of-the-art methodologies,and systematically identifies existing gaps to provide a clear roadmap and targeted research directions,guiding future developments toward the broader adoption and optimal utilization of soft robotic manipulators.
基金financial support from the National Natural Science Foundation of China(NSFC):Grant Nos.22427807 and 62174119Tianjin National Key Laboratory Major Project No.24ZXZSSS00290.
文摘Droplet-based microfluidics have drawn much attention in recent years and have been successfully applied in biochemical analysis,material synthesis,and biomedical engineering.Precise and flexible manipulations of droplets are the basis of various applications.Numerous techniques have been introduced to achieve on-demand control of droplets,including electric,magnetic,acoustic,optical,and thermal methods.Among these,the combination of acoustics and microfluidics(termed acoustofluidics)has shown great potential and advantages in droplet manipulation as it is non-invasive,high-precision,low-cost,easily integrated,and biocompatible.Here,we summarize recent works on acoustofluidic manipulations of droplet-based microfluidics.This paper is structured into three main sections.First,the commonly used acoustic devices in acoustofluidics and their working principles are introduced.Such acoustic devices include interdigital transducers,Lamb wave resonators,and bulk acoustic resonators,and generate acoustic waves with frequencies ranging from kilohertz to gigahertz.Second,the forces and effects involved in droplet manipulations using acoustofluidics are analyzed.Third,the manipulation processes of droplet microfluidics using various acoustofluidic techniques are summarized and compared with other methods,including droplet generation,mixing,splitting,fusion,sorting,transportation,and internal particle patterning.Finally,current challenges and future prospects for acoustofluidic manipulation techniques for droplet-based microfluidics are discussed.
基金Project(U2034211)supported by the National Natural Science Foundation of ChinaProject(20232ACE01013)supported by the Major Scientific and Technological Research and Development Special Project of Jiangxi Province,China。
文摘The safe driving and operation of trains is a necessary condition for ensuring the safe operation of trains.In particular,heavy-haul trains are characterized by the difficulty in driving and operation.Considering the uncertainties in train driving and operation,this paper analyzes the relationship between the safety of heavy-haul electric locomotive hauled trains and driving and operation.It studies the auxiliary intelligent driving safety operation control methods.Through K-means to identify the characteristics of drivers'driving manipulation,the hidden Markov model adaptively adjusts the train driving and operation sequence,and conducts auxiliary driving reconstruction for heavy-haul locomotive driving and operation.Based on the train running curve and the locomotive traction/braking characteristics,it smoothly controls the exertion of the traction/braking force of heavy-haul locomotives,thereby optimizing the driving safety control of heavy-haul trains in the vehicle-environment-track system.Finally,the train operation simulation and optimized driving verification are carried out by simulating some track sections.The results show that the proposed method can correct and pre-optimize driving operations,improving the smoothness of heavy-haul trains by approximately 10%.It verifies the effectiveness of the proposed train assisted driving control reconstruction method,facilitating the smooth and safe operation of heavy-haul trains.
基金the financial support from the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB0470303)the National Key Research and Development Program of China (2022YFB4600101)+5 种基金the National Natural Science Foundation of China (52175201)the Research Program of Science and Technology Department of Gansu Province (24JRRA059, 24JRRA044, and 24YFFA014)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai (AMGM2024F12)the Major Program (ZYFZFX-2) of the Lanzhou Institute of Chemical Physics, CASthe Special Research Assistant Project of the Chinese Academy of Sciencesthe Oasis Scholar of Shihezi University
文摘Octopuses,due to their flexible arms,marvelous adaptability,and powerful suckers,are able to effortlessly grasp and disengage various objects in the marine surrounding without causing devastation.However,manipulating delicate objects such as soft and fragile foods underwater require gentle contact and stable adhesion,which poses a serious challenge to now available soft grippers.Inspired by the sucker infundibulum structure and flexible tentacles of octopus,herein we developed a hydraulically actuated hydrogel soft gripper with adaptive maneuverability by coupling multiple hydrogen bond-mediated supramolecular hydrogels and vat polymerization three-dimensional printing,in which hydrogel bionic sucker is composed of a tunable curvature membrane,a negative pressure cavity,and a pneumatic chamber.The design of the sucker structure with the alterable curvature membrane is conducive to realize the reliable and gentle switchable adhesion of the hydrogel soft gripper.As a proof-of-concept,the adaptive hydrogel soft gripper is capable of implement diversified underwater tasks,including gingerly grasping fragile foods like egg yolks and tofu,as well as underwater robots and vehicles that station-keeping and crawling based on switchable adhesion.This study therefore provides a transformative strategy for the design of novel soft grippers that will render promising utilities for underwater exploration soft robotics.
基金supported in part by the National Science and Technology Council under Grant NSTC 114-2221-E-027-104.
文摘Trajectory tracking for nonlinear robotic systems remains a fundamental yet challenging problem in control engineering,particularly when both precision and efficiency must be ensured.Conventional control methods are often effective for stabilization but may not directly optimize long-term performance.To address this limitation,this study develops an integrated framework that combines optimal control principles with reinforcement learning for a single-link robotic manipulator.The proposed scheme adopts an actor–critic structure,where the critic network approximates the value function associated with the Hamilton–Jacobi–Bellman equation,and the actor network generates near-optimal control signals in real time.This dual adaptation enables the controller to refine its policy online without explicit system knowledge.Stability of the closed-loop system is analyzed through Lyapunov theory,ensuring boundedness of the tracking error.Numerical simulations on the single-link manipulator demonstrate that themethod achieves accurate trajectory followingwhile maintaining lowcontrol effort.The results further showthat the actor–critic learning mechanism accelerates convergence of the control policy compared with conventional optimization-based strategies.This work highlights the potential of reinforcement learning integrated with optimal control for robotic manipulators and provides a foundation for future extensions to more complex multi-degree-of-freedom systems.The proposed controller is further validated in a physics-based virtual Gazebo environment,demonstrating stable adaptation and real-time feasibility.
文摘Military image encryption plays a vital role in ensuring the secure transmission of sensitive visual information from unauthorized access.This paper proposes a new Tri-independent keying method for encrypting military images.The proposed encryption method is based on multilevel security stages of pixel-level scrambling,bitlevel manipulation,and block-level shuffling operations.For having a vast key space,the input password is hashed by the Secure Hash Algorithm 256-bit(SHA-256)for generating independently deterministic keys used in the multilevel stages.A piecewise pixel-level scrambling function is introduced to perform a dual flipping process controlled with an adaptive key for obscuring the spatial relationships between the adjacent pixels.Adynamicmasking scheme is presented for conducting a bit-level manipulation based on distinct keys that change over image regions,providing completely different encryption results on identical regions.To handle the global correlation between large-scale patterns,a chaotic index-map system is employed for shuffling image regions randomly across the image domain based on a logistic map seeded with a private key.Experimental results on a dataset of military images show the effectiveness of the proposed encryption method in producing excellent quantitative and qualitative results.The proposed method obtains uniform histogram distributions,high entropy values around the ideal(≈8 bits),Number of Pixel Change Rate(NPCR)values above 99.5%,and low Peak Signal-to-Noise Ratio(PSNR)over all encrypted images.This validates the robustness of the proposed method against cryptanalytic attacks,verifying its ability to serve as a practical basis for secure image transmission in defense systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204117,12564043,12174076,12074084,and 12074169)the Guangxi Science and Technology Project(Grant Nos.2023GXNSFFA026002,2024GXNSFBA010261,2021GXNSFDA196001,and AD23026117)+3 种基金the Open Project of State Key Laboratory of Surface Physics in Fudan University(Grant No.KF2022_15)the Guangdong Province Talent Recruitment Program(Grant No.2021QN02C103)supported by the Research Grants Council of Hong Kong(Grant Nos.16310422 and AoE/P-502/20)the Innovation Project of Guangxi Graduate Education(Grant No.11241018)。
文摘Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to small particles within the dipole regime or specific light fields,thereby lacking universality and sometimes leading to ambiguity.To overcome these limitations,we establish a fully analytical and comprehensive framework for optical force/torque based on the Cartesian multipole expansion theory,which is applicable to arbitrary-sized bi-isotropic(chiral)spherical particles immersed in arbitrary monochromatic optical fields.Rigorous expressions are thus derived,which explicitly bridge the optical force/torque with particle-propertydependent coefficients and“force/torque source”quantities characterizing the incident light structures.Such quantities identify the ultimate physical origins of optical force/torque and are systematically classified into four categories based on their parity(P)and duality(D)symmetries.Each category interacts selectively with particles exhibiting specific P and D(a)symmetries,thus inducing distinct optical forces or torques with characteristic physical behaviors.This classification establishes the mutual symmetry-breaking criteria necessary for both particles and light beams to generate optical force/torque,offering a physics-based roadmap for engineering optical manipulations such as chirality sorting,light-driven micromotors,and beyond.
基金supported by the Foundation of Yunnan Province(Nos.202301AU070021,202201BE070001-027)the Test Foundation of KUST(No.2022T20210208).
文摘Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on energy storage and conversion applications,such as use as anodes in lithium-ion batteries.In this paper,all-inorganic lead-free halide perovskite Cs_(3)Bi_(2)Cl_(9)powders were synthesized by the grinding method,and the lattice was successfully adjusted via introducing Mn^(2+).The characterization results show that Mn-ion substitution can cause local lattice distortion to restructure the lattice,which will cause a mixed arrangement of[BiCl_(6)]octahedra to improve the performance of the anode material.This new material can provide a feasible solution for solving the problem of low specific capacity anode materials caused by unstable crystal structures,and also indicates that such perovskites with unique crystal structures and lattice tunability have broad application prospects in lithium-ion batteries.
基金co-supported by the National Natural Science Foundation of China(Nos.12102034 and 12125201)the Open Fund of State Key Laboratory of Robotics and Systems(HIT),China。
文摘In-space cable-driven manipulators exhibit several advantages,such as a large range of motion,high dexterity,and lightweight structure.However,kinematic and dynamic analysis play an essential role in designing a cable-driven manipulator.In this paper,the kinematic analysis of a type of cable-driven manipulator is performed,and a motion planning scheme is conducted to actuate this manipulator.Moreover,a flexible multi-body dynamic model of a cable-driven manipulator considering the frictional contact between the cables and pulleys is established.To describe properties such as flexibility,vibration,and variable length of the cable,this paper utilizes reducedorder beam elements of the Absolute Nodal Coordinates Formulation(ANCF)in Arbitrary Lagrangian Eulerian(ALE)framework.Additionally,a virtual element is introduced to model the contact segment in the cable-pulley system.A tension decay factor is employed to account for the friction in the contact segment.To validate the proposed method,a semi-analytical model based on D'Alembert's principle is established.Cross-verification is performed to validate the accuracy of both models.The model is further applied to simulate the rotation of the cable-driven manipulator with different structural parameters and frictional factors.The results from the analyses provide valuable guidance for the design and motion control of the in-space cable-driven manipulator.Finally,a prototype of a single module is manufactured and tested.Ground experiments are carried out to verify the kinematic and dynamic models.
基金supported by the National Natural Science Foundation of China(62403340,62303339)Sichuan Science and Technology Program(2026NSFSC1518)+2 种基金China Postdoctoral Science Foundation(CPSF)(2025T180940,2024M762208)Postdoctoral Fellowship Program of CPSF(GZC20231783)Guangxi Key Laboratory of Brain-Inspired Computing and Intelligent Chips(BCIC-24-K2)。
文摘To address the finite-time tracking control problem for fractional-order nonlinear systems(FONSs) with actuator faults and external disturbance,a novel strategy of the finite-time adaptive fuzzy fault-tolerant controller is presented in this paper by utilizing the finite-time stability theory and fractional-order dynamic surface control scheme combined with backstepping method.A new lemma is developed for analyzing the finite-time stability of FONSs in terms of fractional differential inequality,which modifies some existing results.Fuzzy logic systems are adopted to identify unknown nonlinear characteristics in FONS.In order to compensate for the influence of unknown external disturbance and estimation error for fuzzy logic systems,an auxiliary function is employed to estimate the upper bound of parameters online.Furthermore,a global coordinate transformation is first introduced initially to decouple the fractional-order dynamic system of a specific class of underactuated single-link flexible manipulator systems,thereby transforming it into lower triangular systems.Simulation analyses and experimental results verify the feasibility and effectiveness of finite-time tracking control algorithm.
基金supported by the National Key R&D Program of China (Grant Nos.2023YFA1406002 and 2020YFA0308801)the National Natural Science Foundation of China (NSFC) (Grant Nos.12321004,12174025,12074041,and 12204045)+7 种基金the CAS Superconducting Research Project (Grant No.SCZX-0101)the Fundamental Research Funds for the Central Universities (Grant No.2243300003)the Innovation Program for Quantum Science and Technology (Grant No.2021ZD0302800)supported by the Synergetic Extreme Condition User Facility (SECUF)Analysis & Testing center in Beijing Institute of Technologysupport from the Beijing Institute of Technology Research Fund Program (Grant No.2023CX01027)support from the Beijing Institute of Technology Research Fund Program for Young Scholarssupport from the Beijing Institute of Technology Laboratory Research Project (Grant No.2023BITSYB07)。
文摘The kagome ferrimagnet TbMn_(6)Sn_(6),featuring a pristine Mn kagome lattice,has emerged as a candidate Chern magnet with a large intrinsic anomalous Hall effect(AHE).While chemical substitution can modulate its properties,hydrostatic pressure provides a disorder-free route to manipulate electronic and magnetic interactions.Herein,we investigate the effects of hydrostatic pressure on electrical and magneto-transport in TbMn6Sn6 up to 18.3 GPa.Pressure significantly enhances hysteresis in the magnetoresistance and Hall responses,causing a concurrent monotonic coercive field increase,suggesting the enhancement of interlayer magnetic couplings in a robust c-axis ferrimagnetic order.The intrinsic anomalous Hall conductivity increases considerably from 129.5 S·cm^(−1) at ambient pressure conditions to 448.7 S·cm^(−1) at 14.0 GPa—an enhancement of 247%that is unprecedented among pressure-tuned kagome magnets.Based on density functional theory calculations,we reveal that pressure induces multiple gap openings near the Fermi level,giving rise to pronounced Berry curvature hotspots that may contribute to the AHE.Our results show that pressure can be used to enhance the intrinsic topological responses of this kagome magnet.
基金supported by the National Natural Science Foundation of China(Grant Nos.12375244 and 12135009)the Natural Science Foundation of Hunan Province of China(Grant No.2025JJ30002).
文摘Plasma-based optical elements can withstand laser intensities several orders of magnitude higher than traditional optical elements,making them highly promising for manipulating relativistic intensity laser pulses.In this work,we propose and demonstrate a novel microstructured plasma target,inspired by the design of traditional Fresnel zone plates.The specific target structure causes diffraction of the input laser at each zone,resulting in constructive interference and facilitating effective focusing of the input laser pulse.Three-dimensional particle-in-cell simulation results show that the microstructured plasma target can focus Gaussian laser pulses with an intensity of the order of 10^(22) W/cm^(2)to an intensity exceeding 10^(24) W/cm^(2)with the laser focus spot size approaching the diffraction limit of-0.73μm and laser fluence enhancement by a factor of 46.It is also found that when the microstructured plasma target is modified into a reflective element,laser intensities up to 10^(25) W/cm^(2)may be achieved.This extremely high-intensity tightly focused laser pulse can trigger intense photon radiation when interacting with targets,(e.g.,wire plasma targets),with potential applications in laboratory astrophysics,as well as providing the opportunity to explore phenomena such as vacuum birefringence and quantum electrodynamical cascades.
基金supported by the National Natural Science Foundation of China (Grant Nos.92263208,12104383,12304494,and 12404534)the National Key R&D Program of China (Grant No.2022YFA1404400)+1 种基金the Basic and Frontier Exploration Project Independently Deployed by the Institute of Acoustics,Chinese Academy of Sciences (Grant No.JCQY202403)Fundamental Research Funds for the Central Universities。
文摘The integration of acoustic vortices with chiral exceptional points (CEPs) in ring cavities enables the controlled unidirectional coupling and manipulation of orbital angular momentum (OAM) modes. However, realizing multiple vortex orders within a single cavity remains challenging because non-Hermitian modulations must be tailored for different OAM modes simultaneously. We propose a simple approach for constructing multiple CEPs by arranging resistive and reactive impedance-boundary modulations with specific azimuthal patterns along the inner wall of an acoustic ring cavity. This design allows for independent engineering of multiple OAM eigenmodes and their simultaneous excitation using a single monopole source. As a representative example, we demonstrate first-, second-, and third-order OAM generation in both an exact PT-symmetric cavity with balanced gain and loss and a loss-biased passive counterpart that offers additional chirality control through the chirality-reversal effect. This study provides a flexible and compact framework for generating and manipulating multi-order acoustic OAM modes on non-Hermitian platforms.
基金Supported by National Natural Science Foundation of China(Grant No.52475280)Shaanxi Provincial Natural Science Basic Research Program(Grant No.2025SYSSYSZD-105).
文摘Robots are key to expanding the scope of space applications.The end-to-end training for robot vision-based detection and precision operations is challenging owing to constraints such as extreme environments and high computational overhead.This study proposes a lightweight integrated framework for grasp detection and imitation learning,named GD-IL;it comprises a grasp detection algorithm based on manipulability and Gaussian mixture model(manipulability-GMM),and a grasp trajectory generation algorithm based on a two-stage robot imitation learning algorithm(TS-RIL).In the manipulability-GMM algorithm,we apply GMM clustering and ellipse regression to the object point cloud,propose two judgment criteria to generate multiple candidate grasp bounding boxes for the robot,and use manipulability as a metric for selecting the optimal grasp bounding box.The stages of the TS-RIL algorithm are grasp trajectory learning and robot pose optimization.In the first stage,the robot grasp trajectory is characterized using a second-order dynamic movement primitive model and Gaussian mixture regression(GMM).By adjusting the function form of the forcing term,the robot closely approximates the target-grasping trajectory.In the second stage,a robot pose optimization model is built based on the derived pose error formula and manipulability metric.This model allows the robot to adjust its configuration in real time while grasping,thereby effectively avoiding singularities.Finally,an algorithm verification platform is developed based on a Robot Operating System and a series of comparative experiments are conducted in real-world scenarios.The experimental results demonstrate that GD-IL significantly improves the effectiveness and robustness of grasp detection and trajectory imitation learning,outperforming existing state-of-the-art methods in execution efficiency,manipulability,and success rate.
