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Thermal shock of subsurface material with plastic flow during scuffing

Friction 2023年第1期11卷 64-75页

作者： Chuanwei ZHANG Han ZHAI Dong SUN Dezhi ZHENG Xiaoli ZHAO Le GU Liqin WANG MIIT Key Laboratory of Aerospace Bearing Technology and Equipment Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150080China

The thermal shock of subsurface material with shear instability and severe plastic flow during scuffing was *** scuffing damage of M50 steel was tested using a high-speed rolling-sliding contact test rig,and the transient temperature during scuffing was calculated using the Fourier transform method considering the effects of both frictional heat and plastic *** results show that a thermal shock with a rapid rise and subsequent rapid decrease in the contact temperature is generated in the subsurface *** frictional power intensity generates a high temperature rise,leading to the austenitization of the subsurface ***,the plastic flow is generated in the subsurface layer under the high shear stress,and the resulting plastic strain energy generates a further temperature ***,a rapid decrease in the contact temperature quenches the material,resulting in clear shear slip bands and retained austenite in the subsurface layers of the M50 steel.

关键词： scuffing thermal shock high temperature plastic flow

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DCM-based dynamic stable walking under terrain-induced time-varying disturbances for humanoid robots

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Science China(Technological Sciences) 2025年第4期68卷 105-117页

作者： Yan LUO Chao LIU Jianhua WU Zhenhua XIONG Han DING State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

When humanoid robots attempt to walk on terrain such as shaking platforms,time-varying disturbances are introduced to the support *** abrupt changes of inclination angle can cause the robot to lose balance upon landing,presenting significant challenges for balance control *** address this issue,we propose a novel divergent component of motion(DCM)-based time-varying disturbance walking(DCM-TVDW)*** method allows the robot to walk on rugged surfaces and helps to maintain dynamic balance when subjected to large time-varying *** the DCM-TVDW control method,we first adjust the robot's center of mass and stride height to adapt to transitions between different terrain types via a variable height stabilization method,and hold these quantities constant as base *** then combine DCM with the N-step capturability *** combination allows for dynamic balance through multi-step adjustments from the initially unstable region,thereby extending the robots stability *** and experimental results demonstrate that the DCM-TVDW method enables the SJ-Bruce robot to traverse a dynamically shaking platform with an inclination angle of approximately 22°.

关键词： humanoid robot dynamic balance control capturability time-varying disturbance

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A MIMO Neural Network Integrated with Maximum Likelihood Phase Recovery for Transoceanic Coherent Transmission

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Journal of Lightwave technology 2025年第12期43卷 5536-5544页

作者： Wang, Kaihui Wang, Chen Zheng, Tianqi Long, Jianyu Sang, Bohan Zhou, Wen Yu, Jianjun Fudan University State Key Laboratory of ASIC and System School of Information Science and Technology Shanghai200433 China

We proposed a low-complexity multi-input multi-output neural network integrated with a maximum likelihood phase recovery algorithm (MIMO-NN-BMLPR), which is adopted in long-haul coherent optical communication. Neural network based equalization can effectively overcome the nonlinear distortions induced during long-haul transmission. However, the forward neural network equalizer is difficult to track the phase of coherent optical signals. We integrate an additional maximum likelihood phase recovery layer with the MIMO-NN structure so that the phase noise can be compensated. In this work, 8-channel 100-GBaud dual-polarization (DP) PS-16QAM signals are successfully transmitted over 6400km and satisfy the normalized generalized mutual information (NGMI) threshold at 0.86. The proposed MIMO-NN-BMLPR integrates the low-complexity phase estimation with the NNE to improve the performance. Compared with the traditional DSP structure, the proposal prolongs the distance by 48.84% with a 39.80% complexity reduction. © 1983-2012 IEEE.

关键词： Optical communication

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Experimental demonstration of 220-GHz terahertz signals wireless transmission over 4.6 km

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Science China(Information Sciences) 2025年第1期68卷 386-388页

作者： Yi WEI Jianjun YU Mingxu WANG Xiongwei YANG Qiutong ZHANG Jingwen TAN Bing ZHANG Ying WU Yang HAN Peng TIAN Wen ZHOU Kaihui WANG Feng ZHAO State Key Laboratory of ASIC and System Key Laboratory for Information Science of Electromagnetic Waves (MoE)School of Information Science and Technology Fudan University School of Electronic Engineering Xi'an University of Posts and Telecommunications

The advancement of terahertz (THz) communication technology drives the evolution of wireless communication systems,offering novel pathways and technical means for the development of future 6G communication *** wireless communication systems are often constrained by bandwidth limitations of electronic devices in high frequency ***,THz communication technology leverages the characteristics of electromagnetic waves to transcend these limitations,enabling communication athigher frequencies and wider bandwidths.

关键词： wireless terahertz over demonstration experimental signals transmission

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Fast electrothermal coupling calculation method for supporting digital twin construction of electrical equipment

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High Voltage 2023年第2期8卷 390-400页

作者： Xiaosong Zhu Youyuan Wang Ruixiao Meng Shi Long Shaowen Wu State Key Laboratory of Power Transmission Equipment and System Security and New Technology(Chongqing University) ChongqingChina

The failure of electrical equipment directly or indirectly caused by overheating has become one of the main reasons for equipment *** real-time condition monitoring method of electrical equipment based on digital twin(DT)has received extensive attention and is considered as a technology with great engineering values and excellent application ***,the current calculation of DT mostly relies on the traditional finite element method(CFEM).This method becomes less computationally efficient as the size of the DT increases,especially for electrical equipment with high *** is difficult to meet the requirements real-time calculation in ***,starting from the algorithm optimization and parallel architecture,based on the weighted residual method and stabilised conforming nodal integration,a novel discrete method of electrothermal coupling equation is proposed and the data storage structure of the algorithm from the bottom layer is redesigned,and the corresponding GPU and multi-core CPU parallel framework are ***,taking the high voltage bushing as an example,the correctness of the method in this paper is verified by the CFEM code and commercial software *** the same grid and accuracy requirement,the calculation time is shortened by at least five times than *** the method is easy to extend to other types of multi-physics calculations.

关键词： electrical coupling method

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Bionic Jumping of Humanoid Robot via Online Centroid Trajectory Optimization and High Dynamic Motion Controller

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Journal of Bionic Engineering 2024年第6期21卷 2759-2778页

作者： Xiangji Wang Wei Guo Zhicheng He Rongchao Li Fusheng Zha Lining Sun State Key Laboratory of Robotics and System Harbin Institute of Technology(HIT)Harbin150001China Faculty of Computing Harbin Institute of Technology(HIT)Harbin150001China

The dynamic motion capability of humanoid robots is a key indicator for evaluating their ***,as a typical dynamic motion,is of great significance for enhancing the robot’s flexibility and terrain adaptability in unstructured ***,achieving high-dynamic jumping control of humanoid robots has become a challenge due to the high degree of freedom and strongly coupled dynamic *** idea for this paper originated from the human response process to jumping commands,aiming to achieve online trajectory optimization and jumping motion control of humanoid ***,we employ nonlinear optimization in combination with the Single Rigid Body Model(SRBM)to generate a robot’s Center of Mass(CoM)trajectory that complies with physical constraints and minimizes the angular momentum of the ***,a Model Predictive Controller(MPC)is designed to track and control the CoM trajectory,obtaining the required contact forces at the robot’s ***,a Whole-Body Controller(WBC)is used to generate full-body joint motion trajectories and driving torques,based on the prioritized sequence of tasks designed for the jumping *** control framework proposed in this paper considers the dynamic characteristics of the robot’s jumping process,with a focus on improving the real-time performance of trajectory optimization and the robustness of *** and experimental results demonstrate that our robot successfully executed high jump motions,long jump motions and continuous jump motions under complex working conditions.

关键词： Humanoid robots Jumping motion control Centroid trajectory optimization Optimization and optimal control

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Mechanism of material removal and chip formation of alumina dispersion strengthened copper in micro-milling

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Frontiers of Mechanical Engineering 2025年第1期20卷 27-43页

作者： Chang LIU Chunya WU Xiguang LI Bo HOU Jiahao WU Ruijiang SUN Mingjun CHEN School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Alumina dispersion-strengthened copper (ADSC), as a representative particle-reinforced metal matrix composite (PRMMC), exhibits superior wear resistance and high strength. However, challenges arise in their processability because of the non-uniform material properties of biphasic materials. In particular, limited research has been conducted on the reinforcement mechanism and behavior of particles during material cutting deformation of PRMMC with nanoscale particles. In this study, a cutting simulation model for ADSC was established, separating the nanoscale reinforcement particles from the matrix. This model was utilized to analyze the interactions among particles, matrix, and tool during the cutting process, providing insights into chip formation and fracture. Particles with high strength and hardness are more prone to storing stress concentrations, anchoring themselves at grain boundaries to resist grain fibration, thereby influencing the stress distribution in the cutting deformation zone. Stress concentration around the particles leads to the formation of discontinuous chips, indicating that ADSC with high-volume fractions of particle (VFP) exhibits low cutting continuity, which is consistent with the results of cutting experiments. The tool tip that is in contact with particles experiences stress concentration, thereby accelerating tool wear. Cutting ADSC with 1.1% VFP results in tool blunting, which increases the radius of cutting edge from 0.5 to 1.9 μm, accompanied with remarkable coating delamination and wear. Simulation results indicate that the minimum uncut chip thickness increases from 0.04 to 0.07 μm as VFP increases from 0.3% to 1.1%. In conjunction with scratch experiments, MUCT increases with the augmentation of VFP. Computational analysis of the specific cutting force indicates that particles contribute to the material’s size effect. The results of this study provide theoretical guidance for practical engineering machining of ADSC, indicating its g

关键词： alumina dispersion-strengthened copper particle-reinforced metal matrix composites material removal mechanism micro-milling chip formation minimum uncut chip thickness

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Dynamic Constraint-Driven Event-Triggered Control of Strict-Feedback systems Without Max/Min Values on Irregular Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 569-580页

作者： Zhuwu Shao Yujuan Wang Zeqiang Li Yongduan Song the State Key Laboratory of Power Transmission Equipment&System Security and New Technology and the School of AutomationChongqing UniversityChongqing 400044China IEEE

This work proposes an event-triggered adaptive control approach for a class of uncertain nonlinear systems under irregular *** the constraints considered in most existing papers,here the external irregular constraints are considered and a constraints switching mechanism(CSM)is introduced to circumvent the difficulties arising from irregular output *** on the CSM,a new class of generalized barrier functions are constructed,which allows the control results to be independent of the maximum and minimum values(MMVs)of constraints and thus extends the existing ***,we proposed a novel dynamic constraint-driven event-triggered strategy(DCDETS),under which the stress on signal transmission is reduced greatly and no constraints are violated by making a dynamic trade-off among system state,external constraints,and inter-execution *** is proved that the system output is driven to close to the reference trajectory and the semi-global stability is guaranteed under the proposed control scheme,regardless of the external irregular output *** also verifies the effectiveness and benefits of the proposed method.

关键词： Adaptive control dynamic constraint-driven event-triggered control irregular output constraints nonlinear strict-feed-back systems

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Per-unit Scheme for Integrated Solution of Hybrid Power-water Flow Problem

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Journal of Modern Power systems and Clean Energy 2023年第2期11卷 680-685页

作者： Xia Zhao Hong Tan Luo Wang Mingyi Sun State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina

When applying the widely-used Newton-Raphson(N-R)method to the integrated solution of the hybrid power-water flow problem of the power-water integrated energy system(PW-IES),it is found that there are numerical differences among Jacobian elements,which may yield an ill-conditioned Jacobian matrix and even cause convergence ***,this letter proposes to per-unitize the water distribution network(WDN)to reduce the numerical differences and thus to improve the Jacobian matrix conditioning and the integrated N-R solution to the hybrid power-water flow problem.

关键词： Integrated energy system load flow Newton-Raphson method water distribution network power-water flow

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Multiple Failure Modes of Compressor Station Incorporated into Risk Evaluation of Electricity-gas Integrated Energy systems

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CSEE Journal of Power and Energy systems 2023年第4期9卷 1439-1448页

作者： Yi Tang Yuan Zhao Wenyuan Li Kaigui Xie Juan Yu the State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing UniversityChongqing 400044 China

Multiple failure modes of gas compressor stations have not been modeled into risk evaluation of electricity-gas integrated energy system(EGIES).This paper presents a method to incorporate multiple failure modes of compressor stations with bypass systems in the EGIES risk *** outage models representing multi-states and multi-failure-modes of com-pressor stations and a bi-level Monte Carlo sampling algorithm for the models are developed.A novel network model of EGIES considering compressor stations with multiple failure modes is *** EGIES with a modified RBTS and an 11-node gas system is used to demonstrate the effectiveness of the proposed method and *** indicate that compressor stations have both positive and negative significant impacts on the risk of *** systems for compressor stations can effectively offset the negative *** compressor stations and their station failures in the risk evaluation of EGIES may result in an inaccurate estimation of the system risk levels and even lead to a misleading conclusion in system *** Terms-Compressor station,electricity-gas integrated energy system,multiple failure modes,risk evaluation.

关键词： Compressor station electricity-gas integrated energy system multiple failure modes risk evaluation.

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