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A Comparative Study on Kinematic Calibration for a 3-DOF Parallel Manipulator Using the Complete-Minimal,Inverse-Kinematic and Geometric-Constraint Error Models

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Chinese Journal of Mechanical engineering 2023年第5期36卷 206-230页

作者： Haiyu Wu Lingyu Kong Qinchuan Li Hao Wang Genliang Chen State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Intelligent Robot Research Center Zhejiang LabHangzhou 311100China School of Mechanical Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China

Kinematic calibration is a reliable way to improve the accuracy of parallel manipulators, while the error model dramatically afects the accuracy, reliability, and stability of identifcation results. In this paper, a comparison study on kinematic calibration for a 3-DOF parallel manipulator with three error models is presented to investigate the relative merits of diferent error modeling methods. The study takes into consideration the inverse-kinematic error model, which ignores all passive joint errors, the geometric-constraint error model, which is derived by special geometric constraints of the studied RPR-equivalent parallel manipulator, and the complete-minimal error model, which meets the complete, minimal, and continuous criteria. This comparison focuses on aspects such as modeling complexity, identifcation accuracy, the impact of noise uncertainty, and parameter identifability. To facilitate a more intuitive comparison, simulations are conducted to draw conclusions in certain aspects, including accuracy, the infuence of the S joint, identifcation with noises, and sensitivity indices. The simulations indicate that the complete-minimal error model exhibits the lowest residual values, and all error models demonstrate stability considering noises. Hereafter, an experiment is conducted on a prototype using a laser tracker, providing further insights into the diferences among the three error models. The results show that the residual errors of this machine tool are signifcantly improved according to the identifed parameters, and the complete-minimal error model can approach the measurements by nearly 90% compared to the inverse-kinematic error model. The fndings pertaining to the model process, complexity, and limitations are also instructive for other parallel manipulators.

关键词： Kinematic calibration Parallel manipulator Error modeling Product of exponential(POE)

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Analysis of Stopping Accuracy Deviation of Urban Rail Transit Train in ATO Driving Mode 5th

Analysis of Stopping Accuracy Deviation of Urban Rail Transi...

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5th International Conference on Electrical engineering and Information Technologies for Rail Transportation, EITRT 2021

作者： Lu, Miao Ou, Dongxiu Hua, Zhichen Gu, Lizhong Casco Signal Ltd. Shanghai China Shanghai Railway Intelligent Dispatching Command System Engineering Research Center Shanghai China

ISBN: (纸本)9789811699122

This paper analyzes the impact on the stopping accuracy of urban rail transit trains from the aspects of vehicle braking system, on-board signaling system and actual installation situation on site. This paper specifically elaborates the low-speed braking characteristics in ATO driving mode, and analyzes the impact of the electro-pneumatic conversion of the vehicle braking system at low speeds, the location error generated by the signaling system, and the installation position of the platform screen door on the stopping accuracy. In response to this problem, this paper puts forward corresponding suggestions after analyzing typical cases. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Light rail transit

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A novel policy iteration algorithm for solving the optimal consensus control problem of a discrete-time multiagent system with unknown dynamics

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Science China(Information Sciences) 2023年第8期66卷 269-270页

作者： Wenkai XU Li WANG Shiwen SUN Chengyi XIA Zengqiang CHEN Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology The Engineering Research Center of Learning-Based Intelligent System Ministry of Education College of Artificial Intelligence Nankai University

At present, an increasing number of researchers have noticed the importance of optimal consensus control(OCC) of multiagent systems(MASs) because of their rich practical applications in various areas [1–4]. To accomp...

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DiagLLM: multimodal reasoning with large language model for explainable bearing fault diagnosis

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SCIENCE CHINA Information Sciences 2025年第6期68卷

作者： Jie WANG Tianrui LI Yan YANG Shiqian CHEN Wanming ZHAI School of Computing and Artificial Intelligence Southwest Jiaotong University Chengdu 611756 China Engineering Research Center of Sustainable Urban Intelligent Transportation Ministry of Education Chengdu 611756 China State Key Laboratory of Rail Transit Vehicle System Chengdu 610031 China

Accurate and reliable bearing fault diagnosis is critical for ensuring the safe operation of mechanical *** data-driven methods encounter challenges in training advanced deep learning models, primarily due to the scarcity of fault data and inconsistencies in data ***, these methods often suffer from limited interpretability and reliability, as they lack constraint-guided learning based on the physical mechanisms underlying bearing failures, which hampers their utility in machine condition *** advancements in large language models (LLMs) demonstrate their potential to address these challenges. To this end, we aim to enhance the generalization and interpretability of bearing fault diagnosis by leveraging the capabilities of multimodal ***, a novel framework called DiagLLM is designed to achieve this *** leverages the powerful reasoning capabilities of large language models and incorporates contextual information from both envelope spectrum images and expert knowledge to accurately diagnose bearing *** effectively tune DiagLLM, diagnostic visual instruction-following data are constructed to link fault feature descriptions with signal characteristics, and the entire model is fine-tuned using a parameter-efficient training *** experiments are conducted on two publicly available bearing fault diagnosis datasets, and the results show that DiagLLM outperforms leading baselines, particularly in scenarios with limited data and cross-data generalization.

关键词： large language model fault diagnosis cross-dataset generalization multimodal learning multimodal fusion

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A DQN-Based Approach for Online Service Placement in Mobile Edge computing 16th

A DQN-Based Approach for Online Service Placement in Mobile ...

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16th EAI International Conference on Collaborative computing: Networking, Applications, and Worksharing, CollaborateCom 2020

作者： Jie, Xiaogan Liu, Tong Gao, Honghao Cao, Chenhong Wang, Peng Tong, Weiqin School of Computer Engineering and Science Shanghai University Shanghai China Shanghai Key Laboratory of Data Science Shanghai China Shanghai Institute for Advanced Communication and Data Science Shanghai University Shanghai China Shanghai Engineering Research Center of Intelligent Computing System Shanghai China

ISBN: (纸本)9783030675394

Due to the development of 5G networks, computation intensive applications on mobile devices have emerged, such as augmented reality and video stream analysis. Mobile edge computing is put forward as a new computing paradigm, to meet the low-latency requirements of applications, by moving services from the cloud to the network edge like base stations. Due to the limited storage space and computing capacity of an edge server, service placement is an important issue, determining which services are deployed at edge to serve corresponding tasks. The problem becomes particularly complicated, with considering the stochastic arrivals of tasks, the additional latency incurred by service migration, and the time spent for waiting in queues for processing at edge. Benefiting from reinforcement learning, we propose a deep Q network based approach, by formulating service placement as a Markov decision process. Real-time service placement strategies are output, to minimize the total latency of arrived tasks in a long term. Extensive simulation results demonstrate that our approach works effectively. © 2021, ICST Institute for Computer Sciences, Social Informatics and Telecommunications engineering.

关键词： Reinforcement learning

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An Improved Method for Approximating the Infinite-Horizon Value Function of the Discrete-Time Switched LQR Problem

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Journal of systems Science & Complexity 2024年第1期37卷 22-39页

作者： HOU Tan LI Yuanlong LIN Zongli Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai 200240China Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaCharlottesvilleVA 22904-4743USA

This paper considers the problem of approximating the infinite-horizon value function of the discrete-time switched LQR *** particular,the authors propose a new value iteration method to generate a sequence of monotonically decreasing functions that converges exponentially to the value *** method facilitates us to use coarse approximations resulting from faster but less accurate algorithms for further value iteration,and thus,the proposed approach is capable of achieving a better approximation for a given computation time compared with the existing *** numerical examples are presented in this paper to illustrate the effectiveness of the proposed method.

关键词： Optimal control switched linear systems switched LQR problem.

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An Efficient and Truthful Online Incentive Mechanism for a Social Crowdsensing Network 16th

An Efficient and Truthful Online Incentive Mechanism for a S...

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16th EAI International Conference on Collaborative computing: Networking, Applications, and Worksharing, CollaborateCom 2020

作者： Fang, Lu Liu, Tong Gao, Honghao Cao, Chenhong Li, Weimin Tong, Weiqin School of Computer Engineering and Science Shanghai University Shanghai China Shanghai Key Laboratory of Data Science Shanghai China Shanghai Institute for Advanced Communication and Data Science Shanghai University Shanghai China Shanghai Engineering Research Center of Intelligent Computing System Shanghai China

ISBN: (纸本)9783030675363

Crowdsening plays an important role in spatiotemporal data collection by leveraging ubiquitous smart devices equipped with sensors. Considering rational and strategic device users, designing a truthful incentive mechanism is a crucial issue. Moreover, another key challenge is that there may not exist adequate participating users in reality. To encourage more users to participate, the social relationship among them can be leveraged, as users may be significantly influenced by their social friends. In this paper, we assume recruited users to diffuse uncompleted sensing tasks to their friends, and propose an efficient and truthful online incentive mechanism for a such social crowdsensing network. Specially, we model the time-varying social influence of a user by extending two metrics of node centrality used in social networks. In order to maximize the accumulated social welfare achieved by the network, we design a user selection algorithm and a payment determination algorithm respectively, in which payments given to participants not only depend on data qualities but also related with social influences. We theoretically prove that our mechanism achieves properties of computational efficiency, individual rationality, and truthfulness. Extensive simulations are conducted, and the results show the superiority of our mechanism. © 2021, ICST Institute for Computer Sciences, Social Informatics and Telecommunications engineering.

关键词： Computational efficiency

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Policy iteration-based adaptive optimal control for Markov jump systems: a transition-probability-free asynchronous approach

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Science China(Information Sciences) 2024年第11期67卷 363-364页

作者： Weidi CHENG Chengcheng REN Shuping HE Changyin SUN Key Laboratory of Intelligent Computing and Signal Processing (Ministry of Education) School of Electrical Engineering and Automation Anhui University Anhui Engineering Laboratory of Human-Robot Integration System and Intelligent Equipment School of Electrical Engineering and Automation Anhui University Information Materials and Intelligent Sensing Laboratory of Anhui Province Engineering Research Center of Autonomous Unmanned System Technology (Ministry of Education) School of Artificial Intelligence Anhui University

The controller and filter design problems of Markov jump systems(MJSs) have gained significant attention over the past few decades. These studies include various aspects,including stochastic stabilization [1], optimal tracking control [2], and dissipative filter design [3]. Although numerous publications address the optimal controller design for MJSs, the issue of hidden MJSs, particularly those with mismatched jumping modes between the system and the controller, has rarely been explored.

关键词： Markov processes

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Temperature dependent terahertz giant anisotropy and cycloidal spin wave modes in BiFeO3 single crystal

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Chinese Physics B 2020年第7期29卷 135-140页

作者： Fan Liu Zuanming Jin Xiumei Liu Yuqing Fang Jiajia Guo Yan Peng Zhenxiang Cheng Guohong Ma Yiming Zhu Shanghai Key Laboratory of Modern Optical System and Engineering Research Center of Optical Instrument and System(Ministry of Education)University of Shanghai for Science and TechnologyShanghai 200093China Department of Physics Shanghai UniversityShanghai 200444China Institute for Superconducting and Electronic Materials University of WollongongNSWAustralia SIOM&STU Joint Laboratory for Superintense Lasers and the Applications Shanghai 201210China Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai 200092China

THz time-domain spectroscopy(THz-TDS)is used to study the THz-optical properties of a single crystal bismuth ferrite BiFeO3(BFO).It can be found that the anisotropy of BiFeO3 is strongly dependent on the temperature.A giant birefringence up to around 3.6 is observed at 1 *** presence of a spatially modulated cycloidal antiferromagnetic structure leads to spin cycloid resonances(SCR)ψandΦ,corresponding to the out-of-plane and in-plane modes of the spin cycloid,*** distinguish the SCR with respect to their response to orthogonal polarizations of the electric fields of the incident THz *** addition,we observe a resonance appearing below 140 K,which might be interpreted as an electromagnon mode and related to a spin reorientation *** present observations present that the temperature and polarization,as the external control parameters,can be used to modulate the THz optical properties of BFO single crystal.

关键词： time resolved terahertz spectroscopy dielectric anisotropy spin cycloid resonance

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Multi-objective traffic calming measures for roadways passing through rural communities

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Advances in Transportation Studies 2016年第38期38卷 59-74页

作者： Lu, W. Jiang, Y. Chen, S. Lu, J.J. Wang, C. Transportation Research Center School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University China Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji University Shanghai China College of Transport and Communications Shanghai Maritime University Shanghai China Intelligent Transportation System Research Center Southeast University Nanjing210096 China

This paper evaluates the effectiveness of traffic calming measures from the perspectives of traffic safety performance, environmental and public health impacts and economic benefits. In order to examine their usefulness and applicability to rural roadways passing through small communities, this study applied four traffic calming measures: speed humps, speed tables, raised intersections and roadway narrowings. A driving simulator was used to accurately record driver deceleration, acceleration and lateral offset behavior in built roadway environments, with and without traffic calming measures present. In addition, a vehicle emissions model was used to evaluate the environmental and public health impacts. Furthermore, the cost of each traffic calming measure and the average safety benefit were considered as a function of effectiveness to determine which measures to install. The experimental results show that the most effective treatments were a combination of roadway narrowing and speed tables, except in terms of vehicle emissions. © 2016, Aracne Editrice. All rights reserved.

关键词： Public health

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