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UPPER-BOUND APPROACH ANALYSIS OF DRIVING POWER OF WHEEL FOR CASTEX

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中国有色金属学会会刊：英文版 1999年第1期9卷 101-106页

作者： cao, Furong Shi, Zhiyuan wen, Jinglin Northeastern Univ Shenyang China

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关键词： casting extrusion continuous extrusion upper bound theorem

WAMS-based monitoring and control of Hopf bifurcations in multi-machine power systems

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第6期9卷 840-848页

作者： Shao-bu WANG quan-yuan JIANG Yi-jia cao School of Electrical Engineering Zhejiang University Hangzhou 310027 China

A method is proposed to monitor and control Hopf bifurcations in multi-machine power systems using the information from wide area measurement systems (WAMSs). The power method (PM) is adopted to compute the pair of conjugate eigenvalues with the algebraically largest real part and the corresponding eigenvectors of the Jacobian matrix of a power system. The distance between the current equilibrium point and the Hopf bifurcation set can be monitored dynamically by computing the pair of con- jugate eigenvalues. When the current equilibrium point is close to the Hopf bifurcation set, the approximate normal vector to the Hopf bifurcation set is computed and used as a direction to regulate control parameters to avoid a Hopf bifurcation in the power system described by differential algebraic equations (DAEs). The validity of the proposed method is demonstrated by regulating the reactive power loads in a 14-bus power system.

关键词： Wide area measurement system (WAMS) Hopf bifurcations Monitoring of bifurcations Control of bifurcations

Grasp evaluation and contact points planning for polyhedral objects using a ray-shooting algorithm

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第3期13卷 218-231页

作者： Shuang-quan wen Tie-jun WU Department of Control Science and Engineering Zhejiang UniversityHangzhou 310027China

Grasp evaluation and planning are two fundamental issues in robotic grasping and dexterous manipulation. Most traditional methods for grasp quality evaluation suffer from non-uniformity of the wrench space and a dependence on the scale and choice of the reference frame. To overcome these weaknesses, we present a grasp evaluation method based on disturbance force rejection under the assumption that the normal component of each individual contact force is less than one. The evaluation criterion is solved using an enhanced ray-shooting algorithm in which the geometry of the grasp wrench space is read by the support mapping. This evaluation procedure is very fast due to the efficiency of the ray-shooting algorithm without linearization of the friction cones. Based on a necessary condition for grasp quality improvement, a heuristic searching algorithm for polyhedral object regrasp is also proposed. It starts from an initial force-closure unit grasp configuration and iteratively improves the grasp quality to find the locally optimum contact points. The efficiency and effectiveness of the proposed algorithms are illustrated by a number of numerical examples.

关键词： Force closure Grasp quality evaluation Multifingered grasp Grasping planning Ray-shooting

Thermal-force control ability under variation of electromagnetic stick structure parameters in RPECT

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Journal of Iron and Steel Research International 2024年第1期31卷 224-236页

作者： Ting-song Yang wen-quan Sun Feng-shan Du An-rui He quan Yang National Engineering Research Center of Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing100083China Institute of Engineering and Technology University of Science and Technology BeijingBeijing100083China College of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina

Thermal-force driving of roll profile electromagnetic control technology(RPECT),which can be used to adjust the roll profile,can be affected by the sequential temperature rise between the electromagnetic stick(ES)and electromagnetic control *** to the limited space of ES and induction coil,the cross-sectional area of induction coil can be inevitably affected by changing the size of the ES induction zone,which can further change the energy input under the same electromagnetic parameters,the temperature rising effect and the bulging *** investigate this phenomenon,the effects of the radius of the induction zone on the thermal-force contribution ratio,the heating ability of ES and the temperature distribution were analyzed through an electromagnetic-thermal-structural finite element *** ensure that the results are applicable to RPECT,the thermal energy conversion ability and thermal-force roll crown control ability under different lengths of the induction zone were *** was found that whether the current density regulation mode or the current frequency regulation mode is adopted,the cases with 20 or 25 mm radius of the induction zone have the great thermal energy conversion ability and the good thermal-force roll crown control *** reasonable adjustment of the length of the induction zone can reduce the radius required for the maximum energy efficiency *** with the results of the simulation analysis,the optimization of ES based on the control ability maximization requirement is achieved,which provides the base for the design and configuration of ES in RPECT.

关键词： Roll profile electromagnetic control technology Electromagnetic stick Electromagnetic control roll Induction area Thermal-force driving

QFS-domains and Quasicontinuous Domains

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Acta Mathematica Sinica,English Series 2015年第2期31卷 295-304页

作者： wen Feng ZHANG Xiao quan XU Department of Mathematics Sichuan University School of Mathematics and Computer Science Jiangxi Science & Technology Normal University Department of Mathematics Jiangxi Normal University

In this paper, we show that （1） for each QFS-domain L, L is an ωQFS-domain iff L has a countable base for the Scott topology; （2） the Scott-continuous retracts of QFS-domains are QFS- domains; （3） for a quasicontinuous domain L, L is Lawson compact iff L is a finitely generated upper set and for any x1, x2 ∈ L and finite G1, G2 C L with G1 〈〈 x1, G2 〈〈 x2, there is a finite subset F C L such that ↑ x1 x2 G2; （4） L is a QFS-d0main iff L is a quasicontinuous domain and given any finitely many pairs {（Fi, xi）： Fi is finite, xi ∈ L with Fi 〈〈 xi, 1 ≤i ≤n}, there is a quasi-finitely separating function 5 on L such that Fi 〈〈 δ（xi）〈〈 xi.

关键词： QFS-domain quasicontinuous domain Scott topology Lawson compact

Robust fault diagnosis with disturbance rejection and attenuation for systems with multiple disturbances

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Journal of Systems Engineering and Electronics 2011年第1期22卷 135-140页

作者： Songyin cao Lei Guo Xinyu wen School of Automation Southeast University Nanjing 210096 E R. China School of Instrumentation Science and Opto-Electronics Engineering Beihang University Beijing 100191 Po R. China

The fault diagnosis problem is investigated for a class of nonlinear neutral systems with multiple ***-varying faults are considered and multiple disturbances are supposed to include the unknown disturbance modeled by an exo-system and norm bounded uncertain disturbance.A nonlinear disturbance observer is designed to estimate the modeled ***,the fault diagnosis observer is constructed by integrating disturbance observer with disturbance attenuation and rejection *** augmented Lyapunov functional approach,which involves the tuning parameter and slack variable,is applied to make the solution of inequality more ***,applications for a two-link robotic manipulator system are given to show the efficiency of the proposed approach.

关键词： robust fault diagnosis observer design multiple disturbances anti-disturbance fault diagnosis disturbance rejection and attenuation.

SCKF-STF-CN:a universal nonlinear filter for maneuver target tracking

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第8期12卷 678-686页

作者： quan-bo GE wen-bin LI Cheng-lin wen Institute of Information and Control Hangzhou Dianzi University Hangzhou 310018 China State Key Lab of lndustrial Control Technology Zhejiang University Hangzhou 310027 China

Square-root cubature Kalman filter (SCKF) is more effective for nonlinear state estimation than an unscented Kalman *** this paper,we study the design of nonlinear filters based on SCKF for the system with one step noise correlation and abrupt state ***,we give the SCKF that deals with the one step correlation between process and measurement noises,SCKF-CN in ***,we introduce the idea of a strong tracking filter to construct the adaptive square-root factor of the prediction error covariance with a fading factor,which makes SCKF-CN obtain outstanding tracking performance to the system with target maneuver or abrupt state ***,the tracking performance of SCKF is greatly improved.A universal nonlinear estimator is proposed,which can not only deal with the conventional nonlinear filter problem with high dimensionality and correlated noises,but also achieve an excellent strong tracking performance towards the abrupt change of target *** simulation examples with a bearings-only tracking system are illustrated to verify the efficiency of the proposed algorithms.

关键词： Nonlinear system Maneuver target tracking Correlated noises Square-root cubature Kalman filter (SCKF) Strong tracking filtering (STF)

RANSACs for 3D Rigid Registration:A Comparative Evaluation

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IEEE/CAA Journal of Automatica Sinica 2022年第10期9卷 1861-1878页

作者： Jiaqi Yang Zhiqiang Huang Siwen quan Zhiguo cao Yanning Zhang the National Engineering Laboratory for Integrated Aero-Space-Ground-Ocean Big Data Application Technology School of Computer ScienceNorthwestern Polytechnical UniversityXi’an 710072China the School of Electronic and Control Engineering Chang’an UniversityXi’an 710064China the School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074China IEEE

Estimating an accurate six-degree-of-freedom(6-Do F)pose from correspondences with outliers remains a critical issue to 3D rigid *** sample consensus(RANSAC)and its variants are popular solutions to this *** there have been a number of RANSAC-fashion estimators,two issues remain ***,it is unclear which estimator is more appropriate to a particular ***,the impacts of different sampling strategies,hypothesis generation methods,hypothesis evaluation metrics,and stop criteria on the overall estimators remain *** work fills these gaps by first considering six existing RANSAC-fashion methods and then proposing eight variants for a comprehensive *** objective is to thoroughly compare estimators in the RANSAC family,and evaluate the effects of each key stage on the eventual 6-Do F pose estimation *** have been carried out on four standard datasets with different application scenarios,data modalities,and *** provide us with input correspondence sets with a variety of inlier ratios,spatial distributions,and *** on the experimental results,we summarize remarkable outcomes and valuable findings,so as to give practical instructions to real-world applications,and highlight current bottlenecks and potential solutions in this research realm.

关键词： 3D rigid registration performance evaluation point cloud pose estimation

Zn-Fe and Y-modified Zn-Fe coatings on 42CrMo steel via pack cementation

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Rare Metals 2021年第8期40卷 2266-2274页

作者： Li Liu Si-Rong Yu wen-An cao School of Materials Science and Engineering China University of Petroleum(East China)Qingdao266580China

Zn-Fe and Y-modified Zn-Fe coatings were prepared on 42 CrMo steel through pack cementation processes at 370,390 and 410℃ for 4 h.Y modification was achieved through the co-deposition of Zn and Y_(2)O_(3).The effects of Y modification on microstructure,formation and corrosion behavior of the Zn-Fe coating were *** coating thickness increased with an increase in *** Y-modified Zn-Fe coating was thicker than the plain Zn-Fe *** the Zn-Fe coating and Y-modified Zn-Fe coating showed single-layered structures,but the overall microstructure was improved by Y *** activation energies for Zn-Fe coating and Y-modified Zn-Fe coating were 113.15 and80.65 kJ·mol^(-1),*** Zn-Fe coating consisted of FeZn_(13) and Fe11Zn40 *** effects of Y modification on the corrosion behavior of the Zn-Fe coating were evaluated through an immersion test and polarization *** results showed that the corrosion resistance was improved by Y modification.

关键词： Pack cementation Coating Modification Activation energy Corrosion