The Pseudo-Derivative Feedback (PDF) algorithm is introduced into design of electro-hydraulic speed servos. With limited extra complexity in implementation of controller's electronic circuits, the PDF control enab...The Pseudo-Derivative Feedback (PDF) algorithm is introduced into design of electro-hydraulic speed servos. With limited extra complexity in implementation of controller's electronic circuits, the PDF control enables the electro-hydraulic speed servo to respond to a step command without steady-state error, and also to follow successfully a sinusoidal command at the frequency higher than that the system resulted from traditional design can reach. The numerical example-based comparison in dynamic and static behavior shows also the PDF system is superior to the traditional system in terms of both the capability of handling loads applied to the system and the robustness to ignore variation and uncertainty of the parameters of the hydraulic valve-actuator unit in operation.展开更多
An algorithm for control of several servo motors by a mi- crocontroller is presented. The limited ntanber of progranunable timers on the majority of micnocntrollers presents a problem for multiple generation of timing...An algorithm for control of several servo motors by a mi- crocontroller is presented. The limited ntanber of progranunable timers on the majority of micnocntrollers presents a problem for multiple generation of timing pulses. Two software approaches are discussed in the paper and experimental results given for operation of a set of small servos using a single timer.展开更多
Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical...Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical arms.The performance of the servo drive,which encompasses the response to the torque,efficiency,control bandwidth and the steady-state positioning accuracy,significantly influences the performance of the aviation actuation.Consequently,enhancing the control bandwidth and refining the positioning accuracy of aviation electro-mechanical actuation servo drives have emerged as a focal point of research.This paper investigates the multi-source disturbances present in aviation electro-mechanical actuation servo systems and summarizes recent research on high-performance servo control methods based on active disturbance rejection control(ADRC).We present a comprehensive overview of the research status pertaining to servo control architecture,strategies for suppressing disturbances in the current loop,and ADRC-based strategies for the position loop.We delineate the research challenges and difficulties encountered by aviation electro-mechanical actuation servo drive control technology.展开更多
To enhance the robustness and real-time performance of robotic arm visual servoing in complex environments such as space,this study proposes Di FA-DETR,a modified object detection framework based on the DETR architect...To enhance the robustness and real-time performance of robotic arm visual servoing in complex environments such as space,this study proposes Di FA-DETR,a modified object detection framework based on the DETR architecture.The proposed model incorporates an improved Res Net50 Bottleneck structure with spatial dimensionality reduction and sparse interaction mechanisms,alongside a redesigned self-attention module featuring downsampling optimization and adaptive feature enhancement.A custom-annotated satellite component dataset was constructed to train and evaluate the system.Experimental results demonstrate that Di FA-DETR achieves an AP50 of 79.9%,outperforming existing DETR variants while reducing computational complexity by 31.9%and nearly doubling the inference speed.The method was further validated in a ground-based visual servoing system using an industrial robotic arm and camera setup.The system successfully tracked satellite targets under dynamic motion scenarios,maintaining millimeter-level positioning accuracy.These results confirm the feasibility and effectiveness of the proposed method in supporting future space robotic applications requiring precision tracking and fast response.展开更多
Bio-inspired magnetic helical microrobots have great potential for biomedical and micromanipulation applications. Precise interaction with objects in liquid environments is an important prerequisite and challenge for ...Bio-inspired magnetic helical microrobots have great potential for biomedical and micromanipulation applications. Precise interaction with objects in liquid environments is an important prerequisite and challenge for helical microrobots to perform various tasks. In this study, an automatic control method is proposed to realize the axial docking of helical microrobots with arbitrarily placed cylindrical objects in liquid environments. The docking process is divided into ascent, approach, alignment, and insertion stages. First, a 3D docking path is planned according to the positions and orientations of the microrobot and the target object. Second, a steering-based 3D path-following controller guides the helical microrobot to rise away from the container bottom and approach the target along the path. Third, based on path design with gravity compensation and steering output limits, alignment of position and orientation can be accomplished simultaneously. Finally, the helical microrobot completes the docking under the rotating magnetic field along the target orientation. Experiments verified the automatic docking of the helical microrobot with static targets, including connecting with micro-shafts and inserting into micro-tubes. The object grasping of a reconfigurable helical microrobot aided by 3D automatic docking was also demonstrated. This method enables precise docking of helical microrobots with objects, which might be used for capture and sampling, in vivo navigation control, and functional assembly of microrobots.展开更多
The“visual perception+hand-eye transformation+motion planning”paradigm of robotic coordination grasping has demonstrated feasibility in unstructured scenes such as logistics.However,further developments in handling ...The“visual perception+hand-eye transformation+motion planning”paradigm of robotic coordination grasping has demonstrated feasibility in unstructured scenes such as logistics.However,further developments in handling complex and dynamic environments remain challenging.To address the issue of unknown targets requiring immediate deployment for grasping tasks,this paper proposes a novel hand-eye coordinated method for progressive grasping guided by the texture keypoints of the target.First,we develop an efficient system for acquiring texture-matching templates and an estimation algorithm for the feature region that filters the precisely registered texture feature points of the target.Then,we integrate optical flow estimation to update and track the robust texture region in real time,and design a feature-based servo grasping controller to map the optical flow points of the high-registration texture region to the robot joint velocities for precise tracking.Finally,we impose spatiotemporal constraints on the planned trajectory and decouple the target motion,to achieve progressive approach and rotationally invariant grasping for both dynamic and static targets.Comprehensive experiments demonstrate that this tracking grasping method exhibits a low latency,a high precision,and robustness in complex scenarios and dynamic disturbances,with an average position accuracy of approximately 5 mm,a rotation accuracy of approximately 0.02,and an overall grasping success rate of approximately 90%.展开更多
Robot-assisted surgery has become an indispensable component in modern neurosurgical procedures.However,existing registration methods for neurosurgical robots often rely on high-end hardware and involve prolonged or u...Robot-assisted surgery has become an indispensable component in modern neurosurgical procedures.However,existing registration methods for neurosurgical robots often rely on high-end hardware and involve prolonged or unstable registration times,limiting their applicability in dynamic and time-sensitive intraoperative settings.This paper proposes a novel fully automatic monocular-based registration and real-time tracking method.First,dedicated fiducials are designed,and an automatic preoperative and intraoperative detection method for these fiducials is introduced.Second,a geometric representation of the fiducials is constructed based on a 2D KD-Tree.Through a two-stage optimization process,the depth of 2D fiducials is estimated,and 2D-3D correspondences are established to achieve monocular registration.This approach enables fully automatic intraoperative registration using only a single optical camera.Finally,a six-degree-of-freedom visual servo control strategy inspired by the mass-spring-damper system is proposed.By integrating artificial potential field and admittance control,the strategy ensures real-time responsiveness and stable tracking.Experimental results demonstrate that the proposed method achieves a registration time of 0.23 s per instance with an average error of 0.58 mm.Additionally,the motion performance of the control strategy has been validated.Preliminary experiments verify the effectiveness of MonoTracker in dynamic tracking scenarios.This method holds promise for enhancing the adaptability of neurosurgical robots and offers significant clinical application potential.展开更多
This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanis...This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.展开更多
Computer-aided surgical navigation technology helps and guides doctors to complete the operation smoothly,which simulates the whole surgical environment with computer technology,and then visualizes the whole operation...Computer-aided surgical navigation technology helps and guides doctors to complete the operation smoothly,which simulates the whole surgical environment with computer technology,and then visualizes the whole operation link in three dimensions.At present,common image-guided surgical techniques such as computed tomography(CT)and X-ray imaging(X-ray)will cause radiation damage to the human body during the imaging process.To address this,we propose a novel Extended Kalman filter-based model that tracks the puncture needle-point using an ultrasound probe.To address the limitations of Kalman filteringmethods based on position and velocity,our method of Kalman filtering uses the position and relative velocity of the puncture needle-point instead,and the ultrasonic probe is controlled by a Proportional Integral(PI)controller in X-axis direction and Proportional Derivative(PD)controller in the Y-axis direction.The motion of the ultrasonic probe can be servo-controlled by whether the image information of the puncture needle-point can be detected by the ultrasonic image so that the ultrasonic probe can track the puncture needle-point in real time.The experiment results show that this method has better tracking performance.展开更多
This paper presents a method of multicopter intercep-tion control based on visual servo and virtual tube in a cluttered environment.The proposed hybrid heuristic function improves the efficiency of the A*algorithm.The...This paper presents a method of multicopter intercep-tion control based on visual servo and virtual tube in a cluttered environment.The proposed hybrid heuristic function improves the efficiency of the A*algorithm.The revised objective function makes the virtual tube generating curve not only smooth but also close to the path points generated by the A*algorithm.In six dif-ferent simulation scenarios,the efficiency of the modified A*algorithm is 6.2%higher than that of the traditional A*algorithm.The efficiency of path planning and virtual tube planning is veri-fied by simulations.The effectiveness of interception control is verified by a software-in-loop(SIL)simulation.展开更多
A new suspension gravity compensation system has been developed to alleviate the gravity effects on a two-dimensional(2D)deployable mechanism for ground verification.Considering the rigid-flexible coupling of both the...A new suspension gravity compensation system has been developed to alleviate the gravity effects on a two-dimensional(2D)deployable mechanism for ground verification.Considering the rigid-flexible coupling of both the rotating servo and the suspension system,a multi-body dynamic model simulating their integration is established using Lagrange’s equation.To mitigate instantaneous impact forces due to significant non-plumb effects from passive following in the horizontal direction,an elastic element is added in series with the rope in the vertical suspension system.The dynamic response of this elastic element relative to the rotating servo system is analyzed by the ADAMS software.Simulation results show that the compensating error decreases significantly from 45%to 0.31%when incorporating elastic elements compared to scenarios without such elements.Additionally,low-stiffness elastic elements demonstrate a higher compensating error than high-stiffness ones.A spring with a stiffness coefficient of 6 N/mm is selected in the experiment,ensuring that compensating error meets the design specification of 5%.展开更多
During indoor operations,Unmanned Aerial Vehicles(UAVs)are required to embody attributes such as heightened sensitivity,compact design,and robust maneuverability.A high operational advantage is evident when tasks are ...During indoor operations,Unmanned Aerial Vehicles(UAVs)are required to embody attributes such as heightened sensitivity,compact design,and robust maneuverability.A high operational advantage is evident when tasks are executed using multiple UAVs in unison.Despite the prevalent focus in current UAV research on enhancing discrete components or modules,a holistic,integrated approach that encompasses the UAV architecture,platform design,algorithms,simulation,and swarm intelligence,is lacking.This study introduces a micro-UAV swarm system designed for efficient perception within partially known indoor environments.We devised the comprehensive architectural blueprint of a micro-UAV swarm system.A communication routing evaluation metric is proposed to improve the quality of intercommunication among UAVs in the micro-UAV swarm.In addressing the localization and perception challenges,this study features the development of a multisensor-based autonomous positioning methodology,complemented by an object detection and tracking framework based on YOLOv5 and DeepSORT technologies.In the realm of decision making,we used the DuelingDQN algorithm to facilitate mission allocation and scheduling within the micro-UAV swarm system.For flight control,we introduced a control strategy that integrated pipeline control and visual servoing mechanisms.We developed a dedicated simulation platform and designed a realistic scenario to rigorously validate the efficacy of the entire micro-UAV swarm system in simulated exercises and actual flight tests.展开更多
Hydraulic technology has the outstanding advantages of easy pressure compensation and high power density.It is an indispensable part of subsea equipment,such as deep-sea operations and submersible propulsion.There are...Hydraulic technology has the outstanding advantages of easy pressure compensation and high power density.It is an indispensable part of subsea equipment,such as deep-sea operations and submersible propulsion.There are few studies on electrohydraulic servo valves(EHSVs)in the deep sea.In this work,a novel electro-hydraulic servo rotary valve is designed,and its mathematical model is established.The analysis considers the variations in physical parameters such as temperature,ambient pressure,and oil viscosity resulting from changes in sea depth.This study focuses on the deformation of the rotary valve and the consequent alterations in leakage and friction torque.The findings indicate that at a depth of 12000 m,the fit clearance between the valve spool and the valve sleeve is 0.00413 mm,representing a 17%reduction compared with the clearance in a land environment.Then,the response of the rotary valve to depth is analyzed.The results indicate that the bandwidth of the rotary valve decreases with increasing depth.This study provides a reference for the use of the EHSV in the deep sea.展开更多
The aim of the study is to investigate the impact of the buffer groove structure on the pressure of continuous rotation electro-hydraulic servo motor.The mathematical model of the motor valve plate with triangular gro...The aim of the study is to investigate the impact of the buffer groove structure on the pressure of continuous rotation electro-hydraulic servo motor.The mathematical model of the motor valve plate with triangular groove and U-groove structure is established firstly,and the structure size of the two buffer grooves with better pressure drop effect is obtained by Matlab.Secondly,an established pressure gradient model is developed for the sealed canisters for electric motors using a combined groove structure.The bird swarm optimization algorithm is used to obtain the optimal dimensions for the combined depth and angle of the pressure groove.The flow field in the motor seal chamber is simulated and calculated by Fluent.This study compared the pressure field distributions in the motors sealing chamber using triangular and combined groove structures.It investigated the combined grooves effect on the pressure impact during the commutation of a continuously rotating electro-hydraulic servo motor.It is found that the combined groove structure has a positive impact on reducing the pressure impact.The results indicate that the combined groove structure significantly enhances the efficiency of mitigating pressure shocks when the motor switches between high-and low-pressure chambers.展开更多
At this exhibition,as global expert in jacquard weaving solutions,Jiangsu S&S Intelligent Science And Technology Co.,Ltd.focuses on launching the SLX cam series jacquard machines.This equipment adopts servo direct...At this exhibition,as global expert in jacquard weaving solutions,Jiangsu S&S Intelligent Science And Technology Co.,Ltd.focuses on launching the SLX cam series jacquard machines.This equipment adopts servo direct-drive technology,which can reduce energy consumption by over 20%compared with traditional motor systems,and achieves highprecision control,efficient energy utilization,intelligent control.Precision process design The SLX cam jacquard machine adopts optimized shedding cam curve,featuring long effective shedding time and more stable operation.The low-center-of-gravity design minimizes the vibration and noise of the machine frame,while the camshaft box body formed by one-time processing ensures extremely high mounting accuracy of the conjugate cam.The equipment adopts a fully sealed design,which has good dust-proof effect and attractive appearance.The easily adjustable sensor disc assembly facilitates maintenance.These design details reflect S&S's pursuit of exquisite product quality.展开更多
An enhanced least mean square(LMS)error identification algorithm integrated with Kalman filtering is proposed to resolve accuracy degradation induced by nonlinear dynamics and parameter uncertainties in continuous rot...An enhanced least mean square(LMS)error identification algorithm integrated with Kalman filtering is proposed to resolve accuracy degradation induced by nonlinear dynamics and parameter uncertainties in continuous rotary electro-hydraulic servo systems.This enhancement accelerates convergence and improves accuracy compared with traditional LMS.A fifth-order identification mod-el is developed based on valve-controlled hydraulic motors,with parameters identified using Kalman filter state estimation and gradient smoothing.The results indicate that the improved LMS effectively enhances parameter identification.An advanced disturbance rejection controller(ADRC)is de-signed,and its performance is compared with an optimal proportional integral derivative(PID)con-troller through Simulink simulations.The results show that the ADRC fulfills the control specifications and expands the system’s operational bandwidth.展开更多
This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking...This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking capacity for systems with uncertainties and disturbances. First, SMC discrete equivalent control law is designed on the basis of the nominal model of the system and the adaptive exponential reaching law, and subsequently, stability of the algorithm is analyzed. Second, RBF network is used to f...展开更多
In light of the high nonlinearity of LuGre friction model, a novel method based on ant colony algorithm(ACA) for identifying the friction parameters of flight simulation servo system is proposed. ACA is a parallelized...In light of the high nonlinearity of LuGre friction model, a novel method based on ant colony algorithm(ACA) for identifying the friction parameters of flight simulation servo system is proposed. ACA is a parallelized bionic optimization algorithm inspired from the behavior of real ants, and a kind of positive feedback mechanism is adopted in ACA. On the basis of brief introduction of LuGre friction model, a method for identifying the static LuGre friction parameters and the dynamic LuGre friction parameters using ACA is derived. Finally, this new friction parameter identification scheme is applied to a electric-driven flight simulation servo system with high precision. Simulation and application results verify the feasibility and the effectiveness of the scheme. It provides a new way to identify the friction parameters of LuGre model.展开更多
In present,there are increasing interests in the research on mechanical and control system of underwater vehicles.These ongoing research efforts are motivated by more pervasive applications of such vehicles including ...In present,there are increasing interests in the research on mechanical and control system of underwater vehicles.These ongoing research efforts are motivated by more pervasive applications of such vehicles including seabed oil and gas explorations, scientific deep ocean surveys,military purposes,ecological and water environmental studies,and also entertainments. However,the performance of underwater vehicles with screw type propellers is not prospective in terms of its efficiency and maneuverability.The main weaknesses of this kind of propellers are the production of vortices and sudden generation of thrust forces which make the control of the position and motion difficult. On the other hand,fishes and other aquatic animals are efficient swimmers,posses high maneuverability,are able to follow trajectories,can efficiently stabilize themselves in currents and surges,create less wakes than currently used underwater vehicle, and also have a noiseless propulsion.The fish's locomotion mechanism is mainly controlled by its caudal fin and paired pectoral fins.They are classified into Body and/or Caudal Fin(BCF)and Median and/or paired Pectoral Fins(MPF).The study of highly efficient swimming mechanisms of fish can inspire a better underwater vehicles thruster design and its mechanism. There are few studies on underwater vehicles or fish robots using paired pectoral fins as thruster.The work presented in this paper represents a contribution in this area covering study,design and implementation of locomotion mechanisms of paired pectoral fins in a fish robot.The performance and viability of the biomimetic method for underwater vehicles are highlighted through in-water experiment of a robotic fish.展开更多
Aim To eliminate the influences of backlash nonlinear characteristics generally existing in servo systems, a nonlinear compensation method using backpropagation neural networks(BPNN) is presented. Methods Based on s...Aim To eliminate the influences of backlash nonlinear characteristics generally existing in servo systems, a nonlinear compensation method using backpropagation neural networks(BPNN) is presented. Methods Based on some weapon tracking servo system, a three layer BPNN was used to off line identify the backlash characteristics, then a nonlinear compensator was designed according to the identification results. Results The simulation results show that the method can effectively get rid of the sustained oscillation(limit cycle) of the system caused by the backlash characteristics, and can improve the system accuracy. Conclusion The method is effective on sloving the problems produced by the backlash characteristics in servo systems, and it can be easily accomplished in engineering.展开更多
基金This work is supported by National Natural Science Foundation of china under grant 59475075.
文摘The Pseudo-Derivative Feedback (PDF) algorithm is introduced into design of electro-hydraulic speed servos. With limited extra complexity in implementation of controller's electronic circuits, the PDF control enables the electro-hydraulic speed servo to respond to a step command without steady-state error, and also to follow successfully a sinusoidal command at the frequency higher than that the system resulted from traditional design can reach. The numerical example-based comparison in dynamic and static behavior shows also the PDF system is superior to the traditional system in terms of both the capability of handling loads applied to the system and the robustness to ignore variation and uncertainty of the parameters of the hydraulic valve-actuator unit in operation.
文摘An algorithm for control of several servo motors by a mi- crocontroller is presented. The limited ntanber of progranunable timers on the majority of micnocntrollers presents a problem for multiple generation of timing pulses. Two software approaches are discussed in the paper and experimental results given for operation of a set of small servos using a single timer.
基金supported by the National Natural Science Foundation of China(Nos.52177059 and 52407064).
文摘Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical arms.The performance of the servo drive,which encompasses the response to the torque,efficiency,control bandwidth and the steady-state positioning accuracy,significantly influences the performance of the aviation actuation.Consequently,enhancing the control bandwidth and refining the positioning accuracy of aviation electro-mechanical actuation servo drives have emerged as a focal point of research.This paper investigates the multi-source disturbances present in aviation electro-mechanical actuation servo systems and summarizes recent research on high-performance servo control methods based on active disturbance rejection control(ADRC).We present a comprehensive overview of the research status pertaining to servo control architecture,strategies for suppressing disturbances in the current loop,and ADRC-based strategies for the position loop.We delineate the research challenges and difficulties encountered by aviation electro-mechanical actuation servo drive control technology.
基金supported by the Foundation of National Key Laboratory of Human Factors Engineering,China(No.HFNKL2023 WWO5)。
文摘To enhance the robustness and real-time performance of robotic arm visual servoing in complex environments such as space,this study proposes Di FA-DETR,a modified object detection framework based on the DETR architecture.The proposed model incorporates an improved Res Net50 Bottleneck structure with spatial dimensionality reduction and sparse interaction mechanisms,alongside a redesigned self-attention module featuring downsampling optimization and adaptive feature enhancement.A custom-annotated satellite component dataset was constructed to train and evaluate the system.Experimental results demonstrate that Di FA-DETR achieves an AP50 of 79.9%,outperforming existing DETR variants while reducing computational complexity by 31.9%and nearly doubling the inference speed.The method was further validated in a ground-based visual servoing system using an industrial robotic arm and camera setup.The system successfully tracked satellite targets under dynamic motion scenarios,maintaining millimeter-level positioning accuracy.These results confirm the feasibility and effectiveness of the proposed method in supporting future space robotic applications requiring precision tracking and fast response.
基金supported by the National Natural Science Foundation of China(No.62273117)Pre-research Task(No.SKLRS202418B)of State Key Laboratory of Robotics and Systems(HIT).
文摘Bio-inspired magnetic helical microrobots have great potential for biomedical and micromanipulation applications. Precise interaction with objects in liquid environments is an important prerequisite and challenge for helical microrobots to perform various tasks. In this study, an automatic control method is proposed to realize the axial docking of helical microrobots with arbitrarily placed cylindrical objects in liquid environments. The docking process is divided into ascent, approach, alignment, and insertion stages. First, a 3D docking path is planned according to the positions and orientations of the microrobot and the target object. Second, a steering-based 3D path-following controller guides the helical microrobot to rise away from the container bottom and approach the target along the path. Third, based on path design with gravity compensation and steering output limits, alignment of position and orientation can be accomplished simultaneously. Finally, the helical microrobot completes the docking under the rotating magnetic field along the target orientation. Experiments verified the automatic docking of the helical microrobot with static targets, including connecting with micro-shafts and inserting into micro-tubes. The object grasping of a reconfigurable helical microrobot aided by 3D automatic docking was also demonstrated. This method enables precise docking of helical microrobots with objects, which might be used for capture and sampling, in vivo navigation control, and functional assembly of microrobots.
基金Supported by National Key R&D Program of China(Grant No.2024YFB4709800)Fundamental Research Funds for the Central Universities。
文摘The“visual perception+hand-eye transformation+motion planning”paradigm of robotic coordination grasping has demonstrated feasibility in unstructured scenes such as logistics.However,further developments in handling complex and dynamic environments remain challenging.To address the issue of unknown targets requiring immediate deployment for grasping tasks,this paper proposes a novel hand-eye coordinated method for progressive grasping guided by the texture keypoints of the target.First,we develop an efficient system for acquiring texture-matching templates and an estimation algorithm for the feature region that filters the precisely registered texture feature points of the target.Then,we integrate optical flow estimation to update and track the robust texture region in real time,and design a feature-based servo grasping controller to map the optical flow points of the high-registration texture region to the robot joint velocities for precise tracking.Finally,we impose spatiotemporal constraints on the planned trajectory and decouple the target motion,to achieve progressive approach and rotationally invariant grasping for both dynamic and static targets.Comprehensive experiments demonstrate that this tracking grasping method exhibits a low latency,a high precision,and robustness in complex scenarios and dynamic disturbances,with an average position accuracy of approximately 5 mm,a rotation accuracy of approximately 0.02,and an overall grasping success rate of approximately 90%.
基金Supported by National Natural Science Foundation of China(Grant No.92148206).
文摘Robot-assisted surgery has become an indispensable component in modern neurosurgical procedures.However,existing registration methods for neurosurgical robots often rely on high-end hardware and involve prolonged or unstable registration times,limiting their applicability in dynamic and time-sensitive intraoperative settings.This paper proposes a novel fully automatic monocular-based registration and real-time tracking method.First,dedicated fiducials are designed,and an automatic preoperative and intraoperative detection method for these fiducials is introduced.Second,a geometric representation of the fiducials is constructed based on a 2D KD-Tree.Through a two-stage optimization process,the depth of 2D fiducials is estimated,and 2D-3D correspondences are established to achieve monocular registration.This approach enables fully automatic intraoperative registration using only a single optical camera.Finally,a six-degree-of-freedom visual servo control strategy inspired by the mass-spring-damper system is proposed.By integrating artificial potential field and admittance control,the strategy ensures real-time responsiveness and stable tracking.Experimental results demonstrate that the proposed method achieves a registration time of 0.23 s per instance with an average error of 0.58 mm.Additionally,the motion performance of the control strategy has been validated.Preliminary experiments verify the effectiveness of MonoTracker in dynamic tracking scenarios.This method holds promise for enhancing the adaptability of neurosurgical robots and offers significant clinical application potential.
基金supported by the National Natural Science Foundation under Grant 62273189the Shandong Province Natural Science Foundation under Grant ZR2021MF005Systems Science Plus Joint Research Program of Qingdao University under Grant XT2024201 of China supporting this research work.
文摘This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.
基金supported by the Sichuan Science and Technology Program(2023YFSY0026,2023YFH0004).
文摘Computer-aided surgical navigation technology helps and guides doctors to complete the operation smoothly,which simulates the whole surgical environment with computer technology,and then visualizes the whole operation link in three dimensions.At present,common image-guided surgical techniques such as computed tomography(CT)and X-ray imaging(X-ray)will cause radiation damage to the human body during the imaging process.To address this,we propose a novel Extended Kalman filter-based model that tracks the puncture needle-point using an ultrasound probe.To address the limitations of Kalman filteringmethods based on position and velocity,our method of Kalman filtering uses the position and relative velocity of the puncture needle-point instead,and the ultrasonic probe is controlled by a Proportional Integral(PI)controller in X-axis direction and Proportional Derivative(PD)controller in the Y-axis direction.The motion of the ultrasonic probe can be servo-controlled by whether the image information of the puncture needle-point can be detected by the ultrasonic image so that the ultrasonic probe can track the puncture needle-point in real time.The experiment results show that this method has better tracking performance.
基金supported by the National Natural Science Foundation of China(62303350).
文摘This paper presents a method of multicopter intercep-tion control based on visual servo and virtual tube in a cluttered environment.The proposed hybrid heuristic function improves the efficiency of the A*algorithm.The revised objective function makes the virtual tube generating curve not only smooth but also close to the path points generated by the A*algorithm.In six dif-ferent simulation scenarios,the efficiency of the modified A*algorithm is 6.2%higher than that of the traditional A*algorithm.The efficiency of path planning and virtual tube planning is veri-fied by simulations.The effectiveness of interception control is verified by a software-in-loop(SIL)simulation.
文摘A new suspension gravity compensation system has been developed to alleviate the gravity effects on a two-dimensional(2D)deployable mechanism for ground verification.Considering the rigid-flexible coupling of both the rotating servo and the suspension system,a multi-body dynamic model simulating their integration is established using Lagrange’s equation.To mitigate instantaneous impact forces due to significant non-plumb effects from passive following in the horizontal direction,an elastic element is added in series with the rope in the vertical suspension system.The dynamic response of this elastic element relative to the rotating servo system is analyzed by the ADAMS software.Simulation results show that the compensating error decreases significantly from 45%to 0.31%when incorporating elastic elements compared to scenarios without such elements.Additionally,low-stiffness elastic elements demonstrate a higher compensating error than high-stiffness ones.A spring with a stiffness coefficient of 6 N/mm is selected in the experiment,ensuring that compensating error meets the design specification of 5%.
基金supported by the National Key R&D Program of China(2024YFB4504500)the Shanghai Collaborative Innovation Project(24xtcx00500).
文摘During indoor operations,Unmanned Aerial Vehicles(UAVs)are required to embody attributes such as heightened sensitivity,compact design,and robust maneuverability.A high operational advantage is evident when tasks are executed using multiple UAVs in unison.Despite the prevalent focus in current UAV research on enhancing discrete components or modules,a holistic,integrated approach that encompasses the UAV architecture,platform design,algorithms,simulation,and swarm intelligence,is lacking.This study introduces a micro-UAV swarm system designed for efficient perception within partially known indoor environments.We devised the comprehensive architectural blueprint of a micro-UAV swarm system.A communication routing evaluation metric is proposed to improve the quality of intercommunication among UAVs in the micro-UAV swarm.In addressing the localization and perception challenges,this study features the development of a multisensor-based autonomous positioning methodology,complemented by an object detection and tracking framework based on YOLOv5 and DeepSORT technologies.In the realm of decision making,we used the DuelingDQN algorithm to facilitate mission allocation and scheduling within the micro-UAV swarm system.For flight control,we introduced a control strategy that integrated pipeline control and visual servoing mechanisms.We developed a dedicated simulation platform and designed a realistic scenario to rigorously validate the efficacy of the entire micro-UAV swarm system in simulated exercises and actual flight tests.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC2805703)the Major Training Program of University Research and Innovation Platform of Gansu Provincial Department of Education(Grant No.2024CXPT-09).
文摘Hydraulic technology has the outstanding advantages of easy pressure compensation and high power density.It is an indispensable part of subsea equipment,such as deep-sea operations and submersible propulsion.There are few studies on electrohydraulic servo valves(EHSVs)in the deep sea.In this work,a novel electro-hydraulic servo rotary valve is designed,and its mathematical model is established.The analysis considers the variations in physical parameters such as temperature,ambient pressure,and oil viscosity resulting from changes in sea depth.This study focuses on the deformation of the rotary valve and the consequent alterations in leakage and friction torque.The findings indicate that at a depth of 12000 m,the fit clearance between the valve spool and the valve sleeve is 0.00413 mm,representing a 17%reduction compared with the clearance in a land environment.Then,the response of the rotary valve to depth is analyzed.The results indicate that the bandwidth of the rotary valve decreases with increasing depth.This study provides a reference for the use of the EHSV in the deep sea.
基金Supported by the National Natural Science Foundation of China(No.52375037)the Masters Innovation Project of Beijing University of Civil Engineering and Architecture(No.PG2024142)+1 种基金the Outstanding Youth of Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture(No.GDRC20220801)the Breeding Program Funding of Beijing University of Civil Engineering and Architecture(No.X24026).
文摘The aim of the study is to investigate the impact of the buffer groove structure on the pressure of continuous rotation electro-hydraulic servo motor.The mathematical model of the motor valve plate with triangular groove and U-groove structure is established firstly,and the structure size of the two buffer grooves with better pressure drop effect is obtained by Matlab.Secondly,an established pressure gradient model is developed for the sealed canisters for electric motors using a combined groove structure.The bird swarm optimization algorithm is used to obtain the optimal dimensions for the combined depth and angle of the pressure groove.The flow field in the motor seal chamber is simulated and calculated by Fluent.This study compared the pressure field distributions in the motors sealing chamber using triangular and combined groove structures.It investigated the combined grooves effect on the pressure impact during the commutation of a continuously rotating electro-hydraulic servo motor.It is found that the combined groove structure has a positive impact on reducing the pressure impact.The results indicate that the combined groove structure significantly enhances the efficiency of mitigating pressure shocks when the motor switches between high-and low-pressure chambers.
文摘At this exhibition,as global expert in jacquard weaving solutions,Jiangsu S&S Intelligent Science And Technology Co.,Ltd.focuses on launching the SLX cam series jacquard machines.This equipment adopts servo direct-drive technology,which can reduce energy consumption by over 20%compared with traditional motor systems,and achieves highprecision control,efficient energy utilization,intelligent control.Precision process design The SLX cam jacquard machine adopts optimized shedding cam curve,featuring long effective shedding time and more stable operation.The low-center-of-gravity design minimizes the vibration and noise of the machine frame,while the camshaft box body formed by one-time processing ensures extremely high mounting accuracy of the conjugate cam.The equipment adopts a fully sealed design,which has good dust-proof effect and attractive appearance.The easily adjustable sensor disc assembly facilitates maintenance.These design details reflect S&S's pursuit of exquisite product quality.
基金Supported by the National Natural Science Foundation of China(No.52375037)the Outstanding Youth of Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture(No.GDRC 20220801)+1 种基金the Graduate Innovation Fund Project of Beijing University of Civil Engineering and Architecture(No.PG2025160)the Special Fund for Cultivation Projects of Beijing University of Civil Engineering and Architecture(No.X24026).
文摘An enhanced least mean square(LMS)error identification algorithm integrated with Kalman filtering is proposed to resolve accuracy degradation induced by nonlinear dynamics and parameter uncertainties in continuous rotary electro-hydraulic servo systems.This enhancement accelerates convergence and improves accuracy compared with traditional LMS.A fifth-order identification mod-el is developed based on valve-controlled hydraulic motors,with parameters identified using Kalman filter state estimation and gradient smoothing.The results indicate that the improved LMS effectively enhances parameter identification.An advanced disturbance rejection controller(ADRC)is de-signed,and its performance is compared with an optimal proportional integral derivative(PID)con-troller through Simulink simulations.The results show that the ADRC fulfills the control specifications and expands the system’s operational bandwidth.
文摘This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking capacity for systems with uncertainties and disturbances. First, SMC discrete equivalent control law is designed on the basis of the nominal model of the system and the adaptive exponential reaching law, and subsequently, stability of the algorithm is analyzed. Second, RBF network is used to f...
文摘In light of the high nonlinearity of LuGre friction model, a novel method based on ant colony algorithm(ACA) for identifying the friction parameters of flight simulation servo system is proposed. ACA is a parallelized bionic optimization algorithm inspired from the behavior of real ants, and a kind of positive feedback mechanism is adopted in ACA. On the basis of brief introduction of LuGre friction model, a method for identifying the static LuGre friction parameters and the dynamic LuGre friction parameters using ACA is derived. Finally, this new friction parameter identification scheme is applied to a electric-driven flight simulation servo system with high precision. Simulation and application results verify the feasibility and the effectiveness of the scheme. It provides a new way to identify the friction parameters of LuGre model.
文摘In present,there are increasing interests in the research on mechanical and control system of underwater vehicles.These ongoing research efforts are motivated by more pervasive applications of such vehicles including seabed oil and gas explorations, scientific deep ocean surveys,military purposes,ecological and water environmental studies,and also entertainments. However,the performance of underwater vehicles with screw type propellers is not prospective in terms of its efficiency and maneuverability.The main weaknesses of this kind of propellers are the production of vortices and sudden generation of thrust forces which make the control of the position and motion difficult. On the other hand,fishes and other aquatic animals are efficient swimmers,posses high maneuverability,are able to follow trajectories,can efficiently stabilize themselves in currents and surges,create less wakes than currently used underwater vehicle, and also have a noiseless propulsion.The fish's locomotion mechanism is mainly controlled by its caudal fin and paired pectoral fins.They are classified into Body and/or Caudal Fin(BCF)and Median and/or paired Pectoral Fins(MPF).The study of highly efficient swimming mechanisms of fish can inspire a better underwater vehicles thruster design and its mechanism. There are few studies on underwater vehicles or fish robots using paired pectoral fins as thruster.The work presented in this paper represents a contribution in this area covering study,design and implementation of locomotion mechanisms of paired pectoral fins in a fish robot.The performance and viability of the biomimetic method for underwater vehicles are highlighted through in-water experiment of a robotic fish.
文摘Aim To eliminate the influences of backlash nonlinear characteristics generally existing in servo systems, a nonlinear compensation method using backpropagation neural networks(BPNN) is presented. Methods Based on some weapon tracking servo system, a three layer BPNN was used to off line identify the backlash characteristics, then a nonlinear compensator was designed according to the identification results. Results The simulation results show that the method can effectively get rid of the sustained oscillation(limit cycle) of the system caused by the backlash characteristics, and can improve the system accuracy. Conclusion The method is effective on sloving the problems produced by the backlash characteristics in servo systems, and it can be easily accomplished in engineering.
