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
Serial-parallel manipulators are of great interest to academic community in recent years,especially those composed of classical parallel mechanisms.There have been many studies around 2(3RPS)and 2(3SPR)S-PMs,but unfor...Serial-parallel manipulators are of great interest to academic community in recent years,especially those composed of classical parallel mechanisms.There have been many studies around 2(3RPS)and 2(3SPR)S-PMs,but unfortunately their inverse kinematics have not yet been resolved.This paper discovers that the unknown kinematic parameters of middle platform are responsible for the unresolvable of inverse kinematics,meanwhile the unknown kinematic parameters of middle platform also have huge coupling relationships.Therefore,to break through this challenges,the huge coupling relationships are decoupled layer by layer,the kinematic parameters of middle platform are solved by combining Sylvester's elimination method,and the inverse displacements of 2(3RPS)and 2(3SPR)S-PMs are obtained subsequently.This paper not only solves the inverse kinematics of classical 2(3RPS)and 2(3SPR)S-PMs,but also reveals the essence of the inverse kinematics of general(3-DOF)+(3-DOF)6-DOF S-PMs and proposes a corresponding solution.展开更多
This paper presents a robust finite-time visual servo control strategy for the tracking problem of omni-directional mobile manipulators(OMMs)subject to mismatched disturbances.First,the nonlinear kinematic model of vi...This paper presents a robust finite-time visual servo control strategy for the tracking problem of omni-directional mobile manipulators(OMMs)subject to mismatched disturbances.First,the nonlinear kinematic model of visual servoing for OMMs with mismatched disturbances is explicitly presented to solve the whole-body inverse kinematic problem.Second,a sliding mode observer augmented with an integral terminal sliding mode controller is proposed to handle these uncertainties and ensure that the system converges to a small region around the equilibrium point.The boundary layer technique is employed to mitigate the chattering phenomenon.Furthermore,a strict finite-time Lyapunov stability analysis is conducted.An experimental comparison between the proposed algorithm and a traditional position-based visual servo controller is carried out,and the results demonstrate the superiority of the proposed control algorithm.展开更多
This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link se...This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link serial kinematic chain with 4 Degrees of Freedom(DoF).Decentralised optimal controllers are designed for each link using ADP approach based on a set of cost matrices and data collected from exploration trajectories.The proposed control strategy employs an off-line,off-policy iterative approach to derive four optimal control policies,one for each joint,under exploration strategies.The objective of the controller is to control the position of each joint.Simulation and experimental results show that four independent optimal controllers are found,each under similar exploration strategies,and the proposed ADP approach successfully yields optimal linear control policies despite the presence of these complexities.The experimental results conducted on the Quanser Qarm robotic platform demonstrate the effectiveness of the proposed ADP controllers in handling significant dynamic nonlinearities,such as actuation limitations,output saturation,and filter delays.展开更多
Robotic manipulators increasingly operate in complex three-dimensional workspaces where accuracy and strict limits on position,velocity,and acceleration must be satisfied.Conventional geometric planners emphasize path...Robotic manipulators increasingly operate in complex three-dimensional workspaces where accuracy and strict limits on position,velocity,and acceleration must be satisfied.Conventional geometric planners emphasize path smoothness but often ignore dynamic feasibility,motivating control-aware trajectory generation.This study presents a novel model predictive control(MPC)framework for three-dimensional trajectory planning of robotic manipulators that integrates second-order dynamic modeling and multi-objective parameter optimization.Unlike conventional interpolation techniques such as cubic splines,B-splines,and linear interpolation,which neglect physical constraints and system dynamics,the proposed method generates dynamically feasible trajectories by directly optimizing over acceleration inputs while minimizing both tracking error and control effort.A key innovation lies in the use of Pareto front analysis for tuning prediction horizon and sampling time,enabling a systematic balance between accuracy and motion smoothness.Comparative evaluation using simulated experiments demonstrates that the proposed MPC approach achieves a minimum mean absolute error(MAE)of 0.170 and reduces maximum acceleration to 0.0217,compared to 0.0385 in classical linear methods.The maximum deviation error was also reduced by approximately 27.4%relative to MPC configurations without tuned parameters.All experiments were conducted in a simulation environment,with computational times per control cycle consistently remaining below 20 milliseconds,indicating practical feasibility for real-time applications.Thiswork advances the state-of-the-art inMPC-based trajectory planning by offering a scalable and interpretable control architecture that meets physical constraints while optimizing motion efficiency,thus making it suitable for deployment in safety-critical robotic applications.展开更多
Feedforward control is one of the most effective control techniques to increase the robot’s tracking accuracy.However,most of the dynamic models used in the feedforward controllers are linearly simplified such that t...Feedforward control is one of the most effective control techniques to increase the robot’s tracking accuracy.However,most of the dynamic models used in the feedforward controllers are linearly simplified such that the nonlinear and time-varying characteristics of dynamics in the workspace are ignored.In this paper,an iterative tuning method for feedforward control of parallel manipulators by taking nonlinear dynamics into account is proposed.Based on the robot rigid-body dynamic model,a feedforward controller considering the dynamic nonlinearity is presented.An iterative tuning method is given to iteratively update the feedforward controller by minimizing the root mean square(RMS)of the joint errors at each cycle.The effectiveness and extrapolation capability of the proposed method are validated through the experiments on a 2-DOF parallel manipulator.This research proposes an iterative tuning method for feedforward control of parallel manipulators considering nonlinear dynamics,which has better extrapolation capability in the whole workspace of manipulators.展开更多
Advancements in dynamic modeling methods of robotic manipulator are critical to the effective implementation of model-based control.Traditional approaches rely on rigorous first-principles-based dynamic modeling and p...Advancements in dynamic modeling methods of robotic manipulator are critical to the effective implementation of model-based control.Traditional approaches rely on rigorous first-principles-based dynamic modeling and precise parameter identification,while this paper explores an altemative through data-driven model reconstruction.To tackle the curse of dimensionality in the model reconstruction of a serial robotic manipulator with multi-degree-of-freedom,a relative activation indicator is proposed.Based on this indicator,the k-means clustering algorithm is utilized to classify the data under different working conditions.Sub-sequently,we leverage the fundamental prior knowledge to find the dynamical characteristics of each cluster and reconstruct the dynamic model in a stepwise manner using the method of sparse identification of nonlinear dynamics(SINDy).For the library generation of SINDy,the strategy of double-feature-set for serial manipulators with common joint types is proposed.Simula-tion results show that the stepwise model reconstruction approach not only reduces the size of the library of candidate functions but also decreases the impact of data noise on the reconstruction results.Finally,controllers based on the reconstructed mod.els are deployed on the experimental platform and the experimental results demonstrate the improvement in trajectory tracking performance and the potential of the proposed method in engineering applications.展开更多
In this paper,a novel cooperative collision avoidance control strategy with relative velocity information for redundant robotic manipulators is derived to guarantee the behavioral safety of robots in the cooperative o...In this paper,a novel cooperative collision avoidance control strategy with relative velocity information for redundant robotic manipulators is derived to guarantee the behavioral safety of robots in the cooperative operational task.This strategy can generate the collision-free trajectory of the robotic links in real-time,which is to realize that the robot can avoid moving obstacles less conservatively and ensure tracking accuracy of terminal end-effector tasks in performing cooperative tasks.For the case where there is interference between the moving obstacle and the desired path of the robotic end-effector,the method inherits the null-space-based self-motion characteristics of the redundant manipulator,integrates the relative motion information,and uses the improved artificial potential field method to design the control items,which are used to generate the collision avoidance motion and carry out moving obstacles smoothly and less conservatively.At the same time,the strategy maintains the kinematic constraint relationship of dual-arm cooperatives,to meet the real-time collision avoidance task under collaborative tasks.Finally,the algorithm simulation indicates that the method can better ensure the tracking accuracy of the end-effector task and carry out moving obstacles smoothly.The experimental results show that the method can generate the real-time collision-free trajectory of the robot in the cooperative handling task,and the joint movement is continuous and stable.展开更多
Dear Editor,H_(∞)This letter develops a new framework for the robust stability and performance conditions as well as the relevant controller synthesis with respect to uncertain robot manipulators.There often exist mo...Dear Editor,H_(∞)This letter develops a new framework for the robust stability and performance conditions as well as the relevant controller synthesis with respect to uncertain robot manipulators.There often exist model uncertainties between the nominal model and the real robot manipulator and disturbances. Hence, dealing with their effects plays a crucial role in leading to high tracking performances, as discussed in [1]–[5].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
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
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
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
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
In order to suppress vibration in flexible manipulators, a new type of manipulator mechanism with controllable local degrees of freedom is proposed. This mechanism consists of a main chain and some branch links. The m...In order to suppress vibration in flexible manipulators, a new type of manipulator mechanism with controllable local degrees of freedom is proposed. This mechanism consists of a main chain and some branch links. The main chain is of a flexible open-chain configuration with an end-effector installed at its tip, and the rigid branch links are able to perform active movements. It is proved by kinematics and dynamic analysis that, the branch links bear no direct kinematic relation to the main chain, but their independent motions can strongly affect the dynamic behavior and performance of the flexible manipulator. Then comes a new idea of suppressing vibration, in which independent motions of the branch links are used to suppress the undesired vibration of the flexible main chain through dynamic coupling. On this basis, an optimal method for reducing vibration of flexible manipulators is proposed. Finally, the effectiveness of this method is verified by numerical simulations.展开更多
The control method of highly redundant robot manipulators is introduced. A decentralized autonomous control scheme is used to guide the movement of robot manipulators so that the work done by manipulators is minimized...The control method of highly redundant robot manipulators is introduced. A decentralized autonomous control scheme is used to guide the movement of robot manipulators so that the work done by manipulators is minimized. The method of computing pseudoinverse which needs too many complicated calculation can be avoided. Then the calculation and control of robots are simplified. At the same time system robustness/fault tolerance is achieved.展开更多
In this paper, coordinated control of multiple robot manipulators holding a rigid object is discussed. In consideration of inaccuracy of the dynamic model of a multiple manipulator system, the error equations on obje...In this paper, coordinated control of multiple robot manipulators holding a rigid object is discussed. In consideration of inaccuracy of the dynamic model of a multiple manipulator system, the error equations on object position and internal force are derived. Then a hybrid position/force coordinated learning control scheme is presented and its convergence is proved. The scheme can improve the system performance by modifying the control input of the system after each iterative learning. Simulation results of two planar robot manipulators holding an object show the effectiveness of this control scheme.展开更多
A force control strategy for position controlled robotic manipulators is presented. On line force feedback data are employed to estimate the local shape of the unknown constraint. The estimated vectors are used to ge...A force control strategy for position controlled robotic manipulators is presented. On line force feedback data are employed to estimate the local shape of the unknown constraint. The estimated vectors are used to generate the virtual reference trajectory for the target impedance model that is driven by the force error to produce command position. By following the command position trajectory the robotic manipulator can follow the unknown constraint surface while keeping an acceptable force error in a manner depicted by the target impedance model. Computer simulation on a 3 linked planar manipulator and experimental studies on an Adept 3, an SCARA type robotic manipulator, are conducted to verify the force tracking capability of the proposed control strategy.展开更多
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Supported by National Natural Science Foundation of China(Grant No.52275033)National Natural Science Youth Foundation of China(Grant No.52205033)Hebei Provincial Natural Science Foundation of China(Grant No.E2021203019)。
文摘Serial-parallel manipulators are of great interest to academic community in recent years,especially those composed of classical parallel mechanisms.There have been many studies around 2(3RPS)and 2(3SPR)S-PMs,but unfortunately their inverse kinematics have not yet been resolved.This paper discovers that the unknown kinematic parameters of middle platform are responsible for the unresolvable of inverse kinematics,meanwhile the unknown kinematic parameters of middle platform also have huge coupling relationships.Therefore,to break through this challenges,the huge coupling relationships are decoupled layer by layer,the kinematic parameters of middle platform are solved by combining Sylvester's elimination method,and the inverse displacements of 2(3RPS)and 2(3SPR)S-PMs are obtained subsequently.This paper not only solves the inverse kinematics of classical 2(3RPS)and 2(3SPR)S-PMs,but also reveals the essence of the inverse kinematics of general(3-DOF)+(3-DOF)6-DOF S-PMs and proposes a corresponding solution.
基金supported by the Artificial Intelligence Innovation and Development Special Fund of Shanghai(No.2019RGZN01041)the National Natural Science Foundation of China(No.92048205).
文摘This paper presents a robust finite-time visual servo control strategy for the tracking problem of omni-directional mobile manipulators(OMMs)subject to mismatched disturbances.First,the nonlinear kinematic model of visual servoing for OMMs with mismatched disturbances is explicitly presented to solve the whole-body inverse kinematic problem.Second,a sliding mode observer augmented with an integral terminal sliding mode controller is proposed to handle these uncertainties and ensure that the system converges to a small region around the equilibrium point.The boundary layer technique is employed to mitigate the chattering phenomenon.Furthermore,a strict finite-time Lyapunov stability analysis is conducted.An experimental comparison between the proposed algorithm and a traditional position-based visual servo controller is carried out,and the results demonstrate the superiority of the proposed control algorithm.
基金supported by the DEEPCOBOT project under Grant 306640/O70 funded by the Research Council of Norway.
文摘This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link serial kinematic chain with 4 Degrees of Freedom(DoF).Decentralised optimal controllers are designed for each link using ADP approach based on a set of cost matrices and data collected from exploration trajectories.The proposed control strategy employs an off-line,off-policy iterative approach to derive four optimal control policies,one for each joint,under exploration strategies.The objective of the controller is to control the position of each joint.Simulation and experimental results show that four independent optimal controllers are found,each under similar exploration strategies,and the proposed ADP approach successfully yields optimal linear control policies despite the presence of these complexities.The experimental results conducted on the Quanser Qarm robotic platform demonstrate the effectiveness of the proposed ADP controllers in handling significant dynamic nonlinearities,such as actuation limitations,output saturation,and filter delays.
基金funded by the research project“BR24992947—Development of Robots,Scientific,Technical,and Software for Flexible Robotization and Industrial Automation(RPA)in Automotive Industrial Enterprises in Kazakhstan Using Artificial Intelligence”.
文摘Robotic manipulators increasingly operate in complex three-dimensional workspaces where accuracy and strict limits on position,velocity,and acceleration must be satisfied.Conventional geometric planners emphasize path smoothness but often ignore dynamic feasibility,motivating control-aware trajectory generation.This study presents a novel model predictive control(MPC)framework for three-dimensional trajectory planning of robotic manipulators that integrates second-order dynamic modeling and multi-objective parameter optimization.Unlike conventional interpolation techniques such as cubic splines,B-splines,and linear interpolation,which neglect physical constraints and system dynamics,the proposed method generates dynamically feasible trajectories by directly optimizing over acceleration inputs while minimizing both tracking error and control effort.A key innovation lies in the use of Pareto front analysis for tuning prediction horizon and sampling time,enabling a systematic balance between accuracy and motion smoothness.Comparative evaluation using simulated experiments demonstrates that the proposed MPC approach achieves a minimum mean absolute error(MAE)of 0.170 and reduces maximum acceleration to 0.0217,compared to 0.0385 in classical linear methods.The maximum deviation error was also reduced by approximately 27.4%relative to MPC configurations without tuned parameters.All experiments were conducted in a simulation environment,with computational times per control cycle consistently remaining below 20 milliseconds,indicating practical feasibility for real-time applications.Thiswork advances the state-of-the-art inMPC-based trajectory planning by offering a scalable and interpretable control architecture that meets physical constraints while optimizing motion efficiency,thus making it suitable for deployment in safety-critical robotic applications.
基金Supported by National Natural Science Foundation of China(Grant No.52375502)EU H2020 MSCA R&I Programme(Grant No.101022696).
文摘Feedforward control is one of the most effective control techniques to increase the robot’s tracking accuracy.However,most of the dynamic models used in the feedforward controllers are linearly simplified such that the nonlinear and time-varying characteristics of dynamics in the workspace are ignored.In this paper,an iterative tuning method for feedforward control of parallel manipulators by taking nonlinear dynamics into account is proposed.Based on the robot rigid-body dynamic model,a feedforward controller considering the dynamic nonlinearity is presented.An iterative tuning method is given to iteratively update the feedforward controller by minimizing the root mean square(RMS)of the joint errors at each cycle.The effectiveness and extrapolation capability of the proposed method are validated through the experiments on a 2-DOF parallel manipulator.This research proposes an iterative tuning method for feedforward control of parallel manipulators considering nonlinear dynamics,which has better extrapolation capability in the whole workspace of manipulators.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072237,12472022,12372022,12372065,and U2441202)the Fundamental Research Funds for the Central Universities(Grant No.22120220590)。
文摘Advancements in dynamic modeling methods of robotic manipulator are critical to the effective implementation of model-based control.Traditional approaches rely on rigorous first-principles-based dynamic modeling and precise parameter identification,while this paper explores an altemative through data-driven model reconstruction.To tackle the curse of dimensionality in the model reconstruction of a serial robotic manipulator with multi-degree-of-freedom,a relative activation indicator is proposed.Based on this indicator,the k-means clustering algorithm is utilized to classify the data under different working conditions.Sub-sequently,we leverage the fundamental prior knowledge to find the dynamical characteristics of each cluster and reconstruct the dynamic model in a stepwise manner using the method of sparse identification of nonlinear dynamics(SINDy).For the library generation of SINDy,the strategy of double-feature-set for serial manipulators with common joint types is proposed.Simula-tion results show that the stepwise model reconstruction approach not only reduces the size of the library of candidate functions but also decreases the impact of data noise on the reconstruction results.Finally,controllers based on the reconstructed mod.els are deployed on the experimental platform and the experimental results demonstrate the improvement in trajectory tracking performance and the potential of the proposed method in engineering applications.
基金supported in part by the Advanced Equipment Manufacturing Technology Innovation Project of Hebei Province under Grant No.22311801D,23311807D,and 236Z1816Gin part by the National Natural Science Foundation of China under Grant No.U20A20283.
文摘In this paper,a novel cooperative collision avoidance control strategy with relative velocity information for redundant robotic manipulators is derived to guarantee the behavioral safety of robots in the cooperative operational task.This strategy can generate the collision-free trajectory of the robotic links in real-time,which is to realize that the robot can avoid moving obstacles less conservatively and ensure tracking accuracy of terminal end-effector tasks in performing cooperative tasks.For the case where there is interference between the moving obstacle and the desired path of the robotic end-effector,the method inherits the null-space-based self-motion characteristics of the redundant manipulator,integrates the relative motion information,and uses the improved artificial potential field method to design the control items,which are used to generate the collision avoidance motion and carry out moving obstacles smoothly and less conservatively.At the same time,the strategy maintains the kinematic constraint relationship of dual-arm cooperatives,to meet the real-time collision avoidance task under collaborative tasks.Finally,the algorithm simulation indicates that the method can better ensure the tracking accuracy of the end-effector task and carry out moving obstacles smoothly.The experimental results show that the method can generate the real-time collision-free trajectory of the robot in the cooperative handling task,and the joint movement is continuous and stable.
基金support by “R&D Program for Forest Science Technology(RS-2024-0040 3460)” provided by Korea Forest Service(Korea Forestry Promotion Institute)
文摘Dear Editor,H_(∞)This letter develops a new framework for the robust stability and performance conditions as well as the relevant controller synthesis with respect to uncertain robot manipulators.There often exist model uncertainties between the nominal model and the real robot manipulator and disturbances. Hence, dealing with their effects plays a crucial role in leading to high tracking performances, as discussed in [1]–[5].
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Ministry of Education Important Research Project of Scienceand Technology of China(307005)National Hi-Tech Research and Development Program of China(SQ2007AA04Z231266)
文摘In order to suppress vibration in flexible manipulators, a new type of manipulator mechanism with controllable local degrees of freedom is proposed. This mechanism consists of a main chain and some branch links. The main chain is of a flexible open-chain configuration with an end-effector installed at its tip, and the rigid branch links are able to perform active movements. It is proved by kinematics and dynamic analysis that, the branch links bear no direct kinematic relation to the main chain, but their independent motions can strongly affect the dynamic behavior and performance of the flexible manipulator. Then comes a new idea of suppressing vibration, in which independent motions of the branch links are used to suppress the undesired vibration of the flexible main chain through dynamic coupling. On this basis, an optimal method for reducing vibration of flexible manipulators is proposed. Finally, the effectiveness of this method is verified by numerical simulations.
文摘The control method of highly redundant robot manipulators is introduced. A decentralized autonomous control scheme is used to guide the movement of robot manipulators so that the work done by manipulators is minimized. The method of computing pseudoinverse which needs too many complicated calculation can be avoided. Then the calculation and control of robots are simplified. At the same time system robustness/fault tolerance is achieved.
文摘In this paper, coordinated control of multiple robot manipulators holding a rigid object is discussed. In consideration of inaccuracy of the dynamic model of a multiple manipulator system, the error equations on object position and internal force are derived. Then a hybrid position/force coordinated learning control scheme is presented and its convergence is proved. The scheme can improve the system performance by modifying the control input of the system after each iterative learning. Simulation results of two planar robot manipulators holding an object show the effectiveness of this control scheme.
文摘A force control strategy for position controlled robotic manipulators is presented. On line force feedback data are employed to estimate the local shape of the unknown constraint. The estimated vectors are used to generate the virtual reference trajectory for the target impedance model that is driven by the force error to produce command position. By following the command position trajectory the robotic manipulator can follow the unknown constraint surface while keeping an acceptable force error in a manner depicted by the target impedance model. Computer simulation on a 3 linked planar manipulator and experimental studies on an Adept 3, an SCARA type robotic manipulator, are conducted to verify the force tracking capability of the proposed control strategy.
