查看更多>>摘要：When a curling rock slides on an ice sheet with an initial rotation,a lateral movement occurs,which is known as the curling phenomenon.The force of friction between the curling rock and the ice sheet changes continually with changes in the environment;thus,the sport of curling requires great skill and experience.The throwing of the curling rock is a great challenge in robot design and control,and existing curling robots usually adopt a combination scheme of a wheel chassis and gripper that differs significantly from human throwing movements.A hexapod curling robot that imitates human kicking,sliding,pushing,and curling rock rotating was designed and manufactured by our group,and completed a perfect show during the Beijing 2022 Winter Olympics Games.Smooth switching between the walking and throwing tasks is realized by the robot's morphology transformation based on leg configuration switching.The robot's controlling parameters,which include the kicking velocity vk,pushing velocity vp,orientation angle θc,and rotation velocity ω,are determined by aiming and sliding models according to the estimated equivalent friction coefficient μequ and ratio e of the front and back frictions.The stable errors between the target and actual stopping points converge to 0.2 and 1.105 m in the simulations and experiments,respectively,and the error shown in the experiments is close to that of a well-trained wheelchair curling athlete.This robot holds promise for helping ice-makers rectify ice sheet friction or assisting in athlete training.
Yaqiong LiuShudong SunGaopan ShenXi Vincent Wang...
32-45页
查看更多>>摘要：This paper addresses a multi-agent scheduling problem with uniform parallel machines owned by a resource agent and competing jobs with dynamic arrival times that belong to different consumer agents.All agents are self-interested and rational with the aim of maximizing their own objectives,resulting in intense resource competition among consumer agents and strategic behaviors of unwillingness to dis-close private information.Within the context,a centralized scheduling approach is unfeasible,and a decentralized approach is considered to deal with the targeted problem.This study aims to generate a stable and collaborative solution with high social welfare while simultaneously accommodating con-sumer agents'preferences under incomplete information.For this purpose,a dynamic iterative auction-based approach based on a decentralized decision-making procedure is developed.In the pro-posed approach,a dynamic auction procedure is established for dynamic jobs participating in a real-time auction,and a straightforward and easy-to-implement bidding strategy without price is presented to reduce the complexity of bid determination.In addition,an adaptive Hungarian algorithm is applied to solve the winner determination problem efficiently.A theoretical analysis is conducted to prove that the proposed approach is individually rational and that the myopic bidding strategy is a weakly dominant strategy for consumer agents submitting bids.Extensive computational experiments demonstrate that the developed approach achieves high-quality solutions and exhibits considerable stability on large-scale problems with numerous consumer agents and jobs.A further multi-agent scheduling problem con-sidering multiple resource agents will be studied in future work.
查看更多>>摘要：Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for sup-porting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manufacturing process for fabricating multi-optical-channel atomic vapor cells and an inno-vative method for batch processing the inner sidewalls of millimeter glass holes to meet optical channel requirements.Surface characterization and transmittance tests demonstrate that the processed inner sidewalls satisfy the criteria for an optical channel.In addition,the construction of an integrated process-ing platform enables multilayer non-isothermal anode bonding,the filling of inert gases,and the recovery and recycling of noble gases.Measurements of the absorption spectra and free-induction decay signals of xenon-129(129Xe)and xenon-131(131Xe)under different pump-probe schemes demonstrate the suit-ability of our vapor cell for use in atomic devices including atomic gyroscopes,dual-beam atomic mag-netometers,and other optical/atomic devices.The proposed micromolding technology has broad application prospects in the field of optical-device processing.
查看更多>>摘要：Electroencephalography(EEG)analysis extracts critical information from brain signals,enabling brain disease diagnosis and providing fundamental support for brain-computer interfaces.However,perform-ing an artificial intelligence analysis of EEG signals with high energy efficiency poses significant chal-lenges for electronic processors on edge computing devices,especially with large neural network models.Herein,we propose an EEG opto-processor based on diffractive photonic computing units(DPUs)to process extracranial and intracranial EEG signals effectively and to detect epileptic seizures.The signals of the EEG channels within a second-time window are optically encoded as inputs to the con-structed diffractive neural networks for classification,which monitors the brain state to identify symp-toms of an epileptic seizure.We developed both free-space and integrated DPUs as edge computing systems and demonstrated their applications for real-time epileptic seizure detection using benchmark datasets,that is,the Children's Hospital Boston(CHB)-Massachusetts Institute of Technology(MIT)extracranial and Epilepsy-iEEG-Multicenter intracranial EEG datasets,with excellent computing perfor-mance results.Along with the channel selection mechanism,both numerical evaluations and experimen-tal results validated the sufficiently high classification accuracies of the proposed opto-processors for supervising clinical diagnosis.Our study opens a new research direction for utilizing photonic computing techniques to process large-scale EEG signals and promote broader applications.
查看更多>>摘要：Wide-angle imaging and spectral detection play vital roles in tasks such as target tracking,object classi-fication,and anti-camouflage.However,limited by their intrinsically different architectures,as deter-mined by frequency dispersion requirements,their simultaneous implementation in a shared-aperture system is difficult.Here,we propose a novel concept to realize reconfigurable dual-mode detection based on electrical-control tunable metasurfaces.As a proof-of-concept demonstration,the simultaneous implementation of wide-angle imaging and polarization-spectral detection in a miniature shared-aperture meta-optical system is realized for the first time via the electrical control of cascaded catenary-like metasurfaces.The proposed system supports the imaging(spectral)resolution of approxi-mately 27.8 line-pairs per millimeter(lp.mm-1;～80 nm)for an imaging(spectral)mode from 8 to 14 μm.This system also bears a large field of view of about 70°,enabling multi-target recognition in both modes.This work may promote the miniaturization of multifunctional optical systems,including spec-trometers and polarization imagers,and illustrates the potential industrial applications of meta-optics in biomedicine,security,space exploration,and more.
查看更多>>摘要：This study proposes an image-based visual servoing(IBVS)method based on a velocity observer for an unmanned aerial vehicle(UAV)for tracking a dynamic target in Global Positioning System(GPS)-denied environments.The proposed method derives the simplified and decoupled image dynamics of underactuated UAVs using a constructed virtual camera and then considers the uncertainties caused by the unpredictable rotations and velocities of the dynamic target.A novel image depth model that extends the IBVS method to track a rotating target with arbitrary orientations is proposed.The depth model ensures image feature accuracy and image trajectory smoothness in rotating target tracking.The relative velocities of the UAV and the dynamic target are estimated using the proposed velocity observer.Thanks to the velocity observer,translational velocity measurements are not required,and the control chatter caused by noise-containing measurements is mitigated.An integral-based filter is pro-posed to compensate for unpredictable environmental disturbances in order to improve the anti-disturbance ability.The stability of the velocity observer and IBVS controller is analyzed using the Lyapunov method.Comparative simulations and multistage experiments are conducted to illustrate the tracking stability,anti-disturbance ability,and tracking robustness of the proposed method with a dynamic rotating target.
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