The aim of this study is to propose a novel system that has an ability to detect intra-fractional motion during radiotherapy treatment in real-time using three-dimensional surface taken by a depth camera, Microsoft Ki...The aim of this study is to propose a novel system that has an ability to detect intra-fractional motion during radiotherapy treatment in real-time using three-dimensional surface taken by a depth camera, Microsoft Kinect v1. Our approach introduces three new aspects for three-dimensional surface tracking in radiotherapy treatment. The first aspect is a new algorithm for noise reduction of depth values. Ueda’s algorithm was implemented and enabling a fast least square regression of depth values. The second aspect is an application for detection of patient’s motion at multiple points in thracoabdominal regions. The third aspect is an estimation of three-dimensional surface from multiple depth values. For evaluation of noise reduction by Ueda’s algorithm, two respiratory patterns are measured by the Kinect as well as a laser range meter. The resulting cross correlation coefficients between the laser range meter and the Kinect were 0.982 for abdominal respiration and 0.995 for breath holding. Moreover, the mean cross correlation coefficients between the signals of our system and the signals of Anzai with respect to participant’s respiratory motion were 0.90 for thoracic respiration and 0.93 for abdominal respiration, respectively. These results proved that the performance of the developed system was comparable to existing motion monitoring devices. Reconstruction of three-dimensional surface also enabled us to detect the irregular motion and breathing arrest by comparing the averaged depth with predefined threshold values.展开更多
Evidence⁃based practices of public health will benefit from quantification of passive physical activity assessment.This study aims to investigate the reliability of marker⁃free system(MFS)such as Microsoft Kinect in m...Evidence⁃based practices of public health will benefit from quantification of passive physical activity assessment.This study aims to investigate the reliability of marker⁃free system(MFS)such as Microsoft Kinect in measuring upper extremity motion from different angles.Ten healthy participants performed elbow and shoulder extension/flexion along frontal and median anatomical planes for ten pace⁃controlled repetitions,during which the spatiotemporal positions of upper extremity joints were concurrently recorded by two sensors from 0°and 45°viewing angles.Reliability between the two sensors were evaluated using Pearson correlation coefficient,intra⁃class correlation coefficients,and 95%limits of agreement and coefficient of variation.Worse reliability was observed when possibility of occlusion was higher.However,better reliability was found when longer observation interval(10 s)was used as elementary measuring unit than shorter observation interval(2 s).The overall angular reliability of activity as displacement or changes in angle was not satisfactory.The results are expected to inform the industry for the extension of MFS to clinic applications.展开更多
To extract and tr ack moving objects is usually one of the most important tasks of intelligent video surveillance systems. This paper presents a fast and adaptive background subtraction alg...To extract and tr ack moving objects is usually one of the most important tasks of intelligent video surveillance systems. This paper presents a fast and adaptive background subtraction algorithm and the motion tracking process using this algorithm. The algorithm uses only luminance components of sampled image sequence pixels and models every pixel in a statistical model. The algorithm is characterized by its ability of real time detecting sudden lighting changes, and extracting and tracking motion objects faster. It is shown that our algorithm can be realized with lower time and space complexity and adjustable object detection error rate with comparison to other background subtraction algorithms. Making use of the algorithm, an indoor monitoring system is also worked out and the motion tracking process is presented in this paper. Experimental results testify the algorithm's good performances when used in an indoor monitoring system.展开更多
The accurate assessment of cardiac motion is crucial for diagnosing and monitoring cardiovascular diseases.In this context,digital volume correlation(DVC)has emerged as a promising technique for tracking cardiac motio...The accurate assessment of cardiac motion is crucial for diagnosing and monitoring cardiovascular diseases.In this context,digital volume correlation(DVC)has emerged as a promising technique for tracking cardiac motion from cardiac computed tomography angiographic(CTA)images.This paper presents a comprehensive performance evaluation of the DVC method,specifically focusing on tracking the motion of the left atrium using cardiac CTA data.The study employed a comparative experimental approach while simultaneously optimizing the existing DVC algorithm.Multiple sets of controlled experiments were designed to conduct quantitative analyses on the parameters“radius”and“step”.The results revealed that the optimized DVC algorithm enhanced tracking accuracy within a reasonable computational time.These findings contributed to the understanding of the efficacy and limitations of the DVC algorithm in analyzing heart deformation.展开更多
Motion tracking has attracted great attention in the fields of real-time tracking,nanorobotics,and targeted therapy.For achieving more accurate motion tracking,the highly sensitive position-sensitive detector(PSD)is d...Motion tracking has attracted great attention in the fields of real-time tracking,nanorobotics,and targeted therapy.For achieving more accurate motion tracking,the highly sensitive position-sensitive detector(PSD)is desirable.Here,we demonstrate a meliorated PSD based on graphene-Si heterojunction for motion tracking.The position sensitivity of PSD was improved by employing surface engineering of graphene.Through modulating the transport property of graphene,nearly 20-fold increase of sensitivity was achieved under weak light,and at the same time,the detection limit power was reduced to^2 nW.A motion tracking system was developed based on the improved PSD,and human arm swing was tracked,which demonstrated high sensitivity and real-time tracking capabilities of the PSD.In addition,the PSD can support up to^10 kHz high-frequency tracking.This work provides a new strategy for improving the performance of PSD,and promotes the development of two-dimensional materials in novel optoelectronic devices.展开更多
Motion tracking via Inertial Measurement Units(IMUs)on mobile and wearable devices has attracted significant interest in recent years.High-accuracy IMU-tracking can be applied in various applications,such as indoor na...Motion tracking via Inertial Measurement Units(IMUs)on mobile and wearable devices has attracted significant interest in recent years.High-accuracy IMU-tracking can be applied in various applications,such as indoor navigation,gesture recognition,text input,etc.Many efforts have been devoted to improving IMU-based motion tracking in the last two decades,from early calibration techniques on ships or airplanes,to recent arm motion models used on wearable smart devices.In this paper,we present a comprehensive survey on IMU-tracking techniques on mobile and wearable devices.We also reveal the key challenges in IMU-based motion tracking on mobile and wearable devices and possible directions to address these challenges.展开更多
The aye-aye(Daubentonia madagascariensis)is a nocturnal lemur native to the island of Madagascar with a unique thin middle finger.Its slender third digit has a remarkably specific adaptation,allowing them to perform t...The aye-aye(Daubentonia madagascariensis)is a nocturnal lemur native to the island of Madagascar with a unique thin middle finger.Its slender third digit has a remarkably specific adaptation,allowing them to perform tap-scanning to locate small cavities beneath tree bark and extract wood-boring larvae from it.As an exceptional active acoustic actuator,this finger makes an aye-aye’s biological system an attractive model for pioneering Nondestructive Evaluation(NDE)methods and robotic systems.Despite the important aspects of the topic in the aye-aye’s unique foraging and its potential contribution to the engineering sensory,little is known about the mechanism and dynamics of this unique finger.This paper used a motion-tracking approach for the aye-aye’s middle finger using simultaneous video graphic capture.To mimic the motion,a two-link robot arm model is designed to reproduce the trajectory.Kinematics formulations were proposed to derive the motion of the middle finger using the Lagrangian method.In addition,a hardware model was developed to simulate the aye-aye’s finger motion.To validate the model,different motion states such as trajectory paths and joint angles,were compared.The simulation results indicate the kinematics of the model were consistent with the actual finger movement.This model is used to understand the aye-aye’s unique tap-scanning process for pioneering new tap-testing NDE strategies for various inspection applications.展开更多
A composite nonlinear feedback tracking controller for motion control of robot manipulators is described. The structure of the controller is composed of a composite nonlinear feedback law plus full robot nonlinear dyn...A composite nonlinear feedback tracking controller for motion control of robot manipulators is described. The structure of the controller is composed of a composite nonlinear feedback law plus full robot nonlinear dynamics compensation. The stability is carried out in the presence of friction. The controller takes advantage of varying damping ratios induced by the composite nonlinear feedback control, so the transient performance of the closed-loop is remarkably improved. Simulation results demonstrate the feasibility of the proposed method.展开更多
Object tracking with abrupt motion is an important research topic and has attracted wide attention.To obtain accurate tracking results,an improved particle filter tracking algorithm based on sparse representation and ...Object tracking with abrupt motion is an important research topic and has attracted wide attention.To obtain accurate tracking results,an improved particle filter tracking algorithm based on sparse representation and nonlinear resampling is proposed in this paper. First,the sparse representation is used to compute particle weights by considering the fact that the weights are sparse when the object moves abruptly,so the potential object region can be predicted more precisely. Then,a nonlinear resampling process is proposed by utilizing the nonlinear sorting strategy,which can solve the problem of particle diversity impoverishment caused by traditional resampling methods. Experimental results based on videos containing objects with various abrupt motions have demonstrated the effectiveness of the proposed algorithm.展开更多
A visible magnified and simulated nozzle was designed and installed on a winding machine according to the similarity principle of Reynolds number, to study the yarn motion track in hairiness-reducing nozzle. High-spee...A visible magnified and simulated nozzle was designed and installed on a winding machine according to the similarity principle of Reynolds number, to study the yarn motion track in hairiness-reducing nozzle. High-speed photography was used to observe the yam instantaneous motion state in the nozzle. The results show that the yarn motion track seems to be a cylindrical helix which is close to inner wall in the twisting chamber and kept the same with different technical parameters, such as diameter of the twisting chamber and jet pressure in orifices. According to simulation results and reasonable simplification, the motion track equation and the rotational equation of the yarn could be derived. The velocity of the swirl and hairiness is faster than that of the yarn balloon, so there is enough time for hairiness to be wrapped into the main body of yarn and hence the hairiness is reduced.展开更多
Objective Reliable and objective methods for assessing surgical skill are essential for improving surgical skills and clinical outcomes.While conventional methods rely on subjective evaluations,motion analysis can off...Objective Reliable and objective methods for assessing surgical skill are essential for improving surgical skills and clinical outcomes.While conventional methods rely on subjective evaluations,motion analysis can offer a quantitative alternative.This study aims to use motion tracking data to analyze the motion smoothness and bimanual coordination of various surgical skill levels during laparoscopic surgery.Methods The participants were recruited and grouped into an expert group,an intermediate group,and a novice group on the basis of their experience with laparoscopic surgery.They completed peg transfer,bimanual peg transfer,and rubber band translocation tasks.Motion smoothness was assessed via logarithmic dimensionless tooltip motion jerk,and the dynamic time warping metric of tooltips velocities was employed to assess bimanual coordination.Results Seventeen participants,with four experts,five intermediates,and eight novices,were included.Compared with novices,the experts exhibited smoother motion in both the dominant hand(peg transfer:16.30 vs.18.05,p=0.004;bimanual peg transfer:15.21 vs.17.45,p=0.004;rubber band translocation:14.32 vs.15.87,p=0.004)and non-dominant hand(peg transfer:16.32 vs.18.22,p=0.004;bimanual peg transfer:15.32 vs.17.52,p=0.004;rubber band translocation:14.33 vs.15.77,p=0.004),and superior bimanual coordination(peg transfer:8.77 m/s vs.13.28 m/s,p=0.004;bimanual peg transfer:6.29 m/s vs.11.13 m/s,p=0.004;rubber band translocation:4.50 m/s vs.7.13 m/s,p=0.004)across all tasks.They also outperformed intermediates in motion smoothness in the non-dominant hand and bimanual coordination in the peg transfer(16.32 vs.17.35,p=0.016;8.77 m/s vs.11.89 m/s,p=0.016)and bimanual peg transfer(15.32 vs.16.22,p=0.016;6.29 m/s vs.8.63 m/s,p=0.032)tasks.Similarly,intermediates demonstrated smoother motion in the non-dominant hand(peg transfer:17.35 vs.18.22,p=0.002;bimanual peg transfer:16.22 vs.17.52,p=0.002)and dominant hand(bimanual peg transfer:16.06 vs.17.45,p=0.011),and better bimanual coordination(peg transfer:11.89 m/s vs.13.28 m/s,p=0.002;bimanual peg transfer:8.63 m/s vs.11.13 m/s,p=0.002)than novices did in these tasks.Conclusion This study revealed that motion smoothness and bimanual coordination are capable of facilitating surgical skill differentiation across various skill levels.These findings underscore the utility of motion metrics for objective surgical skill assessment,potentially reducing the subjectivity,bias,and associated costs of conventional assessment approaches.展开更多
Pelvic floor dysfunction is a common morbidity with a negative impact on quality of life. These disorders include multiple clinical conditions which range from urinary and defecatory disorders to sexual disorders, aff...Pelvic floor dysfunction is a common morbidity with a negative impact on quality of life. These disorders include multiple clinical conditions which range from urinary and defecatory disorders to sexual disorders, affecting 24% of women. Since the pelvic floor is one of the most complex regions in the human body, in order to perform an accurate diagnosis, it is important to combine history taking, physical examination and imaging. While in the past, diagnosis of pelvic floor dysfunction was done using history taking and physical examination alone, it had been recognized the need for imaging as well. In the last decades different imaging modalities have been in use, including magnetic resonance imaging and computerized tomography scanning and, nowadays, the use of ultrasonography is gaining popularity. Ultrasound technology is evolving, with technology for 3D, 4D, Doppler and more, making it optimal for pelvic floor imaging. In this paper we review the different ultrasound modalities for pelvic floor imaging. The purpose of this review is to introduce the emerging ultrasound technologies for pelvic floor imaging including volume render mode, fusion imaging, framing, motion tracking and color vector mapping and elastography. The different ultrasonography modalities have resulted to be very useful for the diagnosis and assessment of pelvic floor dysfunctions, they are characterized by availability, short time, low cost, and radiation free. However, the effectiveness of the analysis is operator-dependent.展开更多
This paper is devoted to the problem of modeling and adaptive motion/force tracking for a class of nonholonomic dynamic systems with affine constraints(NDSAC): a vertical wheel on a rotating table. Prior to the develo...This paper is devoted to the problem of modeling and adaptive motion/force tracking for a class of nonholonomic dynamic systems with affine constraints(NDSAC): a vertical wheel on a rotating table. Prior to the development of tracking controller,the dynamic model of the wheel in question is derived in a meticulous manner. A continuously differentiable friction model is also considered in the modeling. By exploiting the inherent cascade interconnected structure of the wheel dynamics, an adaptive motion/force tracking controller is presented guaranteeing that the trajectory tracking errors asymptotically converge to zero while the contact force tracking errors can be made small enough by tuning design parameters. Simulation results are provided to validate the effectiveness of the proposed tracking methodology.展开更多
In order to realize the optimal design of the industrial robot arm structure,an optimization method of the industrial robot arm structure based on green manufacturing technology is proposed.The stability of arm struct...In order to realize the optimal design of the industrial robot arm structure,an optimization method of the industrial robot arm structure based on green manufacturing technology is proposed.The stability of arm structure parameter acquisition can be controlled.The quantitative adjustment model of structural optimization parameters is constructed.The differential fusion control of the arm structure is realized.This paper analyzes the structure parameter law of the robot arm.We use dynamic parameter prediction and output torque parameter compensation method to control the arm structure.According to the adaptive iterative processing results,the arm structure parameter identification is realized.According to the identification results,the cutting parameter optimization method is adopted for the analytical control of the arm structure,and finally the optimized design of the industrial robot arm structure is realized through the green manufacturing technology.The simulation test results show that for the accuracy of the industrial robot arm structure design,this method is better,the output stability is higher,and the arm motion trajectory has a low deviation from the actual motion trajectory,which improves the optimization control and design capabilities of the industrial robot arm structure.展开更多
Resilient motion planning and control,without prior knowledge of disturbances,are crucial to ensure the safe and robust flight of quadrotors.The development of a motion planning and control architecture for quadrotors...Resilient motion planning and control,without prior knowledge of disturbances,are crucial to ensure the safe and robust flight of quadrotors.The development of a motion planning and control architecture for quadrotors,considering both internal and external disturbances(i.e.,motor damages and suspended payloads),is addressed.Firstly,the authors introduce the use of exponential functions to formulate trajectory planning.This choice is driven by its ability to predict thrust responses with minimal computational overhead.Additionally,a reachability analysis is incorporated for error dynamics resulting from multiple disturbances.This analysis sits at the interface between the planner and controller,contributing to the generation of more robust and safe spatial–temporal trajectories.Lastly,the authors employ a cascade controller,with the assistance of internal and external loop observers,to further enhance resilience and compensate the disturbances.The authors’benchmark experiments demonstrate the effectiveness of the proposed strategy in enhancing flight safety,particularly when confronted with motor damages and payload disturbances.展开更多
In today’s society,parallel manipulators(PMs)are widely used in industrial production,aerospace,and other fields,where their forward kinematic analyses often serve as the foundation for various tasks,such as design,c...In today’s society,parallel manipulators(PMs)are widely used in industrial production,aerospace,and other fields,where their forward kinematic analyses often serve as the foundation for various tasks,such as design,calibration,and control.In the past few decades,this issue has seemingly been repeatedly addressed using various numerical methods,intelligent algorithms,and algebraic tools.While it is undeniable that solving the equations is easier with current technology,the problem of“how to formulate solvable equations”is often overlooked.This analysis issue typically involves establishing non-linear,multi-parameter,high-dimensional,and strong-coupled mathematical equations,which,from a geometric perspective,is also considered a process of solving a spatial polyhedron.When considering the temporal dimension of motion between two isomorphic polytopes,based on calculus theory,it has been found that this non-linear problem can be transformed into the superposition of multiple iteratively linear equations.Consequently,we propose an original method for the forward kinematic analysis of PMs,namely the finite-step-integration(FSI)method.In this study,the mathematical principles and modeling methods of the FSI method are elucidated,and the modeling and programming processes of the FSI method are demonstrated using general 6-UPS and 3-UPS/S manipulators as examples.Through the analysis of its unique algebraic structure,the methods for singularity determination and motion tracking characteristic analysis are investigated.This method addresses the long-standing challenges in the forward kinematic modeling of PMs,which is applicable for design,calibration,and control,while also offering novel insights for modeling and solving certain non-linear engineering problems.展开更多
Multiple object tracking （MOT） poses many difficulties to conventional well-studied single object tracking （SOT） algorithms, such as severe expansion of configuration space, high complexity of motion conditions, a...Multiple object tracking （MOT） poses many difficulties to conventional well-studied single object tracking （SOT） algorithms, such as severe expansion of configuration space, high complexity of motion conditions, and visual ambiguities among nearby targets, among which the visual ambiguity problem is the central challenge. In this paper, we address this problem by embedding adaptive mixture observation models （AMOM） into a mixture tracker which is implemented in Particle Filter framework. In AMOM, the extracted multiple features for appearance description are combined according to their discriminative power between ambiguity prone objects, where the discriminability of features are evaluated by online entropy-based feature selection techniques. The induction of AMOM can help to surmount the incapability of conventional mixture tracker in handling object occlusions, and meanwhile retain its merits of flexibility and high efficiency. The final experiments show significant improvement in MOT scenarios compared with other methods.展开更多
In order to obtain stable and high-precision motion tracking in mixed reality(MR)simulation of the complex system,an optical-inertial hybrid tracking method is proposed,which combines the accuracy of optical motion ca...In order to obtain stable and high-precision motion tracking in mixed reality(MR)simulation of the complex system,an optical-inertial hybrid tracking method is proposed,which combines the accuracy of optical motion capture equipment and the robustness of inertial motion capture equipment,and can reduce the occlusion problem of entity scene on the premise of ensuring the localization accuracy.The method has been applied to the ergonomic evaluation of large civil aircraft development processes,and the effectiveness and usability of the method have been verified.展开更多
文摘The aim of this study is to propose a novel system that has an ability to detect intra-fractional motion during radiotherapy treatment in real-time using three-dimensional surface taken by a depth camera, Microsoft Kinect v1. Our approach introduces three new aspects for three-dimensional surface tracking in radiotherapy treatment. The first aspect is a new algorithm for noise reduction of depth values. Ueda’s algorithm was implemented and enabling a fast least square regression of depth values. The second aspect is an application for detection of patient’s motion at multiple points in thracoabdominal regions. The third aspect is an estimation of three-dimensional surface from multiple depth values. For evaluation of noise reduction by Ueda’s algorithm, two respiratory patterns are measured by the Kinect as well as a laser range meter. The resulting cross correlation coefficients between the laser range meter and the Kinect were 0.982 for abdominal respiration and 0.995 for breath holding. Moreover, the mean cross correlation coefficients between the signals of our system and the signals of Anzai with respect to participant’s respiratory motion were 0.90 for thoracic respiration and 0.93 for abdominal respiration, respectively. These results proved that the performance of the developed system was comparable to existing motion monitoring devices. Reconstruction of three-dimensional surface also enabled us to detect the irregular motion and breathing arrest by comparing the averaged depth with predefined threshold values.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51708152)the Science and Technology Innovation Committee of Shenzhen Municipality(Grant No.JCYJ20170811155435737).
文摘Evidence⁃based practices of public health will benefit from quantification of passive physical activity assessment.This study aims to investigate the reliability of marker⁃free system(MFS)such as Microsoft Kinect in measuring upper extremity motion from different angles.Ten healthy participants performed elbow and shoulder extension/flexion along frontal and median anatomical planes for ten pace⁃controlled repetitions,during which the spatiotemporal positions of upper extremity joints were concurrently recorded by two sensors from 0°and 45°viewing angles.Reliability between the two sensors were evaluated using Pearson correlation coefficient,intra⁃class correlation coefficients,and 95%limits of agreement and coefficient of variation.Worse reliability was observed when possibility of occlusion was higher.However,better reliability was found when longer observation interval(10 s)was used as elementary measuring unit than shorter observation interval(2 s).The overall angular reliability of activity as displacement or changes in angle was not satisfactory.The results are expected to inform the industry for the extension of MFS to clinic applications.
文摘To extract and tr ack moving objects is usually one of the most important tasks of intelligent video surveillance systems. This paper presents a fast and adaptive background subtraction algorithm and the motion tracking process using this algorithm. The algorithm uses only luminance components of sampled image sequence pixels and models every pixel in a statistical model. The algorithm is characterized by its ability of real time detecting sudden lighting changes, and extracting and tracking motion objects faster. It is shown that our algorithm can be realized with lower time and space complexity and adjustable object detection error rate with comparison to other background subtraction algorithms. Making use of the algorithm, an indoor monitoring system is also worked out and the motion tracking process is presented in this paper. Experimental results testify the algorithm's good performances when used in an indoor monitoring system.
基金supported by the Australian Research Council(ARC)(Grant No.DP200103492)the National Natural Science Foundation of China(Grant Nos.12172089,12372307,and 61821002)+2 种基金Medical Research Future Fund(Grant Nos.2016165 and 2023977)the CBT Early Career Researcher Grant funded and the Roland Bishop Biomedical Engineering Research Award by Queensland University of Technologythe Springboard Funding and the Global Collaboration Funding by London South Bank University.Computational resources and services used in this work were provided by the High-Performance Computing and Research Support Group,Queensland University of Technology,Brisbane,Australia.
文摘The accurate assessment of cardiac motion is crucial for diagnosing and monitoring cardiovascular diseases.In this context,digital volume correlation(DVC)has emerged as a promising technique for tracking cardiac motion from cardiac computed tomography angiographic(CTA)images.This paper presents a comprehensive performance evaluation of the DVC method,specifically focusing on tracking the motion of the left atrium using cardiac CTA data.The study employed a comparative experimental approach while simultaneously optimizing the existing DVC algorithm.Multiple sets of controlled experiments were designed to conduct quantitative analyses on the parameters“radius”and“step”.The results revealed that the optimized DVC algorithm enhanced tracking accuracy within a reasonable computational time.These findings contributed to the understanding of the efficacy and limitations of the DVC algorithm in analyzing heart deformation.
基金China Postdoctoral Science Foundation,Grant/Award Number:2018M632197Funding of Natural Science Research Projects in Colleges and Universities of Jiangsu Province,Grant/Award Number:18KJD140003+3 种基金National Natural Science Foundation of China,Grant/Award Numbers:11704068,61774034the Fundamental Research Funds for the Central Universities,Grant/Award Number:2242019R20025The National Key Research and Development Program of China,Grant/Award Number:2017YFA0205700the Strategic Priority Research Program of Chinese Academy of Sciences,Grant/Award Number:XDB30000000。
文摘Motion tracking has attracted great attention in the fields of real-time tracking,nanorobotics,and targeted therapy.For achieving more accurate motion tracking,the highly sensitive position-sensitive detector(PSD)is desirable.Here,we demonstrate a meliorated PSD based on graphene-Si heterojunction for motion tracking.The position sensitivity of PSD was improved by employing surface engineering of graphene.Through modulating the transport property of graphene,nearly 20-fold increase of sensitivity was achieved under weak light,and at the same time,the detection limit power was reduced to^2 nW.A motion tracking system was developed based on the improved PSD,and human arm swing was tracked,which demonstrated high sensitivity and real-time tracking capabilities of the PSD.In addition,the PSD can support up to^10 kHz high-frequency tracking.This work provides a new strategy for improving the performance of PSD,and promotes the development of two-dimensional materials in novel optoelectronic devices.
基金part supported by the National Key R&D Program of China(No.2018YFB1004800)the National Natural Science Foundation of China(No.61932013)。
文摘Motion tracking via Inertial Measurement Units(IMUs)on mobile and wearable devices has attracted significant interest in recent years.High-accuracy IMU-tracking can be applied in various applications,such as indoor navigation,gesture recognition,text input,etc.Many efforts have been devoted to improving IMU-based motion tracking in the last two decades,from early calibration techniques on ships or airplanes,to recent arm motion models used on wearable smart devices.In this paper,we present a comprehensive survey on IMU-tracking techniques on mobile and wearable devices.We also reveal the key challenges in IMU-based motion tracking on mobile and wearable devices and possible directions to address these challenges.
基金supported by the National Science Foundation,United States(ECCS-1542015)as part of the National Nanotechnology Coordinated Infrastructure(NNCI).
文摘The aye-aye(Daubentonia madagascariensis)is a nocturnal lemur native to the island of Madagascar with a unique thin middle finger.Its slender third digit has a remarkably specific adaptation,allowing them to perform tap-scanning to locate small cavities beneath tree bark and extract wood-boring larvae from it.As an exceptional active acoustic actuator,this finger makes an aye-aye’s biological system an attractive model for pioneering Nondestructive Evaluation(NDE)methods and robotic systems.Despite the important aspects of the topic in the aye-aye’s unique foraging and its potential contribution to the engineering sensory,little is known about the mechanism and dynamics of this unique finger.This paper used a motion-tracking approach for the aye-aye’s middle finger using simultaneous video graphic capture.To mimic the motion,a two-link robot arm model is designed to reproduce the trajectory.Kinematics formulations were proposed to derive the motion of the middle finger using the Lagrangian method.In addition,a hardware model was developed to simulate the aye-aye’s finger motion.To validate the model,different motion states such as trajectory paths and joint angles,were compared.The simulation results indicate the kinematics of the model were consistent with the actual finger movement.This model is used to understand the aye-aye’s unique tap-scanning process for pioneering new tap-testing NDE strategies for various inspection applications.
基金supported by the National Natural Science Foundation of China (60428303)
文摘A composite nonlinear feedback tracking controller for motion control of robot manipulators is described. The structure of the controller is composed of a composite nonlinear feedback law plus full robot nonlinear dynamics compensation. The stability is carried out in the presence of friction. The controller takes advantage of varying damping ratios induced by the composite nonlinear feedback control, so the transient performance of the closed-loop is remarkably improved. Simulation results demonstrate the feasibility of the proposed method.
基金Supported by the National Natural Science Foundation of China(61701029)
文摘Object tracking with abrupt motion is an important research topic and has attracted wide attention.To obtain accurate tracking results,an improved particle filter tracking algorithm based on sparse representation and nonlinear resampling is proposed in this paper. First,the sparse representation is used to compute particle weights by considering the fact that the weights are sparse when the object moves abruptly,so the potential object region can be predicted more precisely. Then,a nonlinear resampling process is proposed by utilizing the nonlinear sorting strategy,which can solve the problem of particle diversity impoverishment caused by traditional resampling methods. Experimental results based on videos containing objects with various abrupt motions have demonstrated the effectiveness of the proposed algorithm.
基金Tianjin Science and Technology Planning Projects,China(No.04310471)
文摘A visible magnified and simulated nozzle was designed and installed on a winding machine according to the similarity principle of Reynolds number, to study the yarn motion track in hairiness-reducing nozzle. High-speed photography was used to observe the yam instantaneous motion state in the nozzle. The results show that the yarn motion track seems to be a cylindrical helix which is close to inner wall in the twisting chamber and kept the same with different technical parameters, such as diameter of the twisting chamber and jet pressure in orifices. According to simulation results and reasonable simplification, the motion track equation and the rotational equation of the yarn could be derived. The velocity of the swirl and hairiness is faster than that of the yarn balloon, so there is enough time for hairiness to be wrapped into the main body of yarn and hence the hairiness is reduced.
文摘Objective Reliable and objective methods for assessing surgical skill are essential for improving surgical skills and clinical outcomes.While conventional methods rely on subjective evaluations,motion analysis can offer a quantitative alternative.This study aims to use motion tracking data to analyze the motion smoothness and bimanual coordination of various surgical skill levels during laparoscopic surgery.Methods The participants were recruited and grouped into an expert group,an intermediate group,and a novice group on the basis of their experience with laparoscopic surgery.They completed peg transfer,bimanual peg transfer,and rubber band translocation tasks.Motion smoothness was assessed via logarithmic dimensionless tooltip motion jerk,and the dynamic time warping metric of tooltips velocities was employed to assess bimanual coordination.Results Seventeen participants,with four experts,five intermediates,and eight novices,were included.Compared with novices,the experts exhibited smoother motion in both the dominant hand(peg transfer:16.30 vs.18.05,p=0.004;bimanual peg transfer:15.21 vs.17.45,p=0.004;rubber band translocation:14.32 vs.15.87,p=0.004)and non-dominant hand(peg transfer:16.32 vs.18.22,p=0.004;bimanual peg transfer:15.32 vs.17.52,p=0.004;rubber band translocation:14.33 vs.15.77,p=0.004),and superior bimanual coordination(peg transfer:8.77 m/s vs.13.28 m/s,p=0.004;bimanual peg transfer:6.29 m/s vs.11.13 m/s,p=0.004;rubber band translocation:4.50 m/s vs.7.13 m/s,p=0.004)across all tasks.They also outperformed intermediates in motion smoothness in the non-dominant hand and bimanual coordination in the peg transfer(16.32 vs.17.35,p=0.016;8.77 m/s vs.11.89 m/s,p=0.016)and bimanual peg transfer(15.32 vs.16.22,p=0.016;6.29 m/s vs.8.63 m/s,p=0.032)tasks.Similarly,intermediates demonstrated smoother motion in the non-dominant hand(peg transfer:17.35 vs.18.22,p=0.002;bimanual peg transfer:16.22 vs.17.52,p=0.002)and dominant hand(bimanual peg transfer:16.06 vs.17.45,p=0.011),and better bimanual coordination(peg transfer:11.89 m/s vs.13.28 m/s,p=0.002;bimanual peg transfer:8.63 m/s vs.11.13 m/s,p=0.002)than novices did in these tasks.Conclusion This study revealed that motion smoothness and bimanual coordination are capable of facilitating surgical skill differentiation across various skill levels.These findings underscore the utility of motion metrics for objective surgical skill assessment,potentially reducing the subjectivity,bias,and associated costs of conventional assessment approaches.
文摘Pelvic floor dysfunction is a common morbidity with a negative impact on quality of life. These disorders include multiple clinical conditions which range from urinary and defecatory disorders to sexual disorders, affecting 24% of women. Since the pelvic floor is one of the most complex regions in the human body, in order to perform an accurate diagnosis, it is important to combine history taking, physical examination and imaging. While in the past, diagnosis of pelvic floor dysfunction was done using history taking and physical examination alone, it had been recognized the need for imaging as well. In the last decades different imaging modalities have been in use, including magnetic resonance imaging and computerized tomography scanning and, nowadays, the use of ultrasonography is gaining popularity. Ultrasound technology is evolving, with technology for 3D, 4D, Doppler and more, making it optimal for pelvic floor imaging. In this paper we review the different ultrasound modalities for pelvic floor imaging. The purpose of this review is to introduce the emerging ultrasound technologies for pelvic floor imaging including volume render mode, fusion imaging, framing, motion tracking and color vector mapping and elastography. The different ultrasonography modalities have resulted to be very useful for the diagnosis and assessment of pelvic floor dysfunctions, they are characterized by availability, short time, low cost, and radiation free. However, the effectiveness of the analysis is operator-dependent.
基金supported by the National Natural Science Foundation of China(6127309161403227+3 种基金61403228)the Ph.D.Programs Foundation of Ministry of Education of Chinathe Fundamental Research Funds for the Central Universities(KYLX15 0116)the Project of Taishan Scholar of Shandong Province of China
文摘This paper is devoted to the problem of modeling and adaptive motion/force tracking for a class of nonholonomic dynamic systems with affine constraints(NDSAC): a vertical wheel on a rotating table. Prior to the development of tracking controller,the dynamic model of the wheel in question is derived in a meticulous manner. A continuously differentiable friction model is also considered in the modeling. By exploiting the inherent cascade interconnected structure of the wheel dynamics, an adaptive motion/force tracking controller is presented guaranteeing that the trajectory tracking errors asymptotically converge to zero while the contact force tracking errors can be made small enough by tuning design parameters. Simulation results are provided to validate the effectiveness of the proposed tracking methodology.
基金the Research Fund of Faculty of Engineering,University of Malaya(Grant No.GPF052A-2018)
文摘In order to realize the optimal design of the industrial robot arm structure,an optimization method of the industrial robot arm structure based on green manufacturing technology is proposed.The stability of arm structure parameter acquisition can be controlled.The quantitative adjustment model of structural optimization parameters is constructed.The differential fusion control of the arm structure is realized.This paper analyzes the structure parameter law of the robot arm.We use dynamic parameter prediction and output torque parameter compensation method to control the arm structure.According to the adaptive iterative processing results,the arm structure parameter identification is realized.According to the identification results,the cutting parameter optimization method is adopted for the analytical control of the arm structure,and finally the optimized design of the industrial robot arm structure is realized through the green manufacturing technology.The simulation test results show that for the accuracy of the industrial robot arm structure design,this method is better,the output stability is higher,and the arm motion trajectory has a low deviation from the actual motion trajectory,which improves the optimization control and design capabilities of the industrial robot arm structure.
基金National Natural Science Foundation of China,Grant/Award Numbers:62303412,62322314China Postdoctoral Science Foundation,Grant/Award Number:2022M722739Natural Science Foundation of Zhejiang Province,Grant/Award Number:2023YZ01。
文摘Resilient motion planning and control,without prior knowledge of disturbances,are crucial to ensure the safe and robust flight of quadrotors.The development of a motion planning and control architecture for quadrotors,considering both internal and external disturbances(i.e.,motor damages and suspended payloads),is addressed.Firstly,the authors introduce the use of exponential functions to formulate trajectory planning.This choice is driven by its ability to predict thrust responses with minimal computational overhead.Additionally,a reachability analysis is incorporated for error dynamics resulting from multiple disturbances.This analysis sits at the interface between the planner and controller,contributing to the generation of more robust and safe spatial–temporal trajectories.Lastly,the authors employ a cascade controller,with the assistance of internal and external loop observers,to further enhance resilience and compensate the disturbances.The authors’benchmark experiments demonstrate the effectiveness of the proposed strategy in enhancing flight safety,particularly when confronted with motor damages and payload disturbances.
基金supported by the National Natural Science Foundation of China(Grant Nos.52105035 and 62203094)the Special Central Funds for Guiding Local Scientific and Technological Development,China(Grant No.236Z1801G)+2 种基金the Higher Education Youth Top Talent Project of Hebei Province,China(Grant No.BJK2024042)the Natural Science Foundation of Hebei Province,China(Grant Nos.E2021203109 and F2023501021)the Graduate Student Innovation Capability Training and Support Project of Hebei Province,China(Grant No.CXZZBS2024053).
文摘In today’s society,parallel manipulators(PMs)are widely used in industrial production,aerospace,and other fields,where their forward kinematic analyses often serve as the foundation for various tasks,such as design,calibration,and control.In the past few decades,this issue has seemingly been repeatedly addressed using various numerical methods,intelligent algorithms,and algebraic tools.While it is undeniable that solving the equations is easier with current technology,the problem of“how to formulate solvable equations”is often overlooked.This analysis issue typically involves establishing non-linear,multi-parameter,high-dimensional,and strong-coupled mathematical equations,which,from a geometric perspective,is also considered a process of solving a spatial polyhedron.When considering the temporal dimension of motion between two isomorphic polytopes,based on calculus theory,it has been found that this non-linear problem can be transformed into the superposition of multiple iteratively linear equations.Consequently,we propose an original method for the forward kinematic analysis of PMs,namely the finite-step-integration(FSI)method.In this study,the mathematical principles and modeling methods of the FSI method are elucidated,and the modeling and programming processes of the FSI method are demonstrated using general 6-UPS and 3-UPS/S manipulators as examples.Through the analysis of its unique algebraic structure,the methods for singularity determination and motion tracking characteristic analysis are investigated.This method addresses the long-standing challenges in the forward kinematic modeling of PMs,which is applicable for design,calibration,and control,while also offering novel insights for modeling and solving certain non-linear engineering problems.
基金Supported by National Natural Science Foundation of China (Grant No.60573167)National High-Tech Research and Development Program of China (Grant No.2006AA01Z118)National Basic Research Program of China (Grant No.2006CB303103)
文摘Multiple object tracking （MOT） poses many difficulties to conventional well-studied single object tracking （SOT） algorithms, such as severe expansion of configuration space, high complexity of motion conditions, and visual ambiguities among nearby targets, among which the visual ambiguity problem is the central challenge. In this paper, we address this problem by embedding adaptive mixture observation models （AMOM） into a mixture tracker which is implemented in Particle Filter framework. In AMOM, the extracted multiple features for appearance description are combined according to their discriminative power between ambiguity prone objects, where the discriminability of features are evaluated by online entropy-based feature selection techniques. The induction of AMOM can help to surmount the incapability of conventional mixture tracker in handling object occlusions, and meanwhile retain its merits of flexibility and high efficiency. The final experiments show significant improvement in MOT scenarios compared with other methods.
基金This work was supported by the National Key R&D Program of China(No.2018YFB1701600).
文摘In order to obtain stable and high-precision motion tracking in mixed reality(MR)simulation of the complex system,an optical-inertial hybrid tracking method is proposed,which combines the accuracy of optical motion capture equipment and the robustness of inertial motion capture equipment,and can reduce the occlusion problem of entity scene on the premise of ensuring the localization accuracy.The method has been applied to the ergonomic evaluation of large civil aircraft development processes,and the effectiveness and usability of the method have been verified.
