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Torque estimation for robotic joint with harmonic drive transmission based on system dynamic characteristics

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Journal of Systems Engineering and Electronics 2022年第6期33卷 1320-1331页

作者： ZHU Minghong xiao shu YU Fei Faculty of Electrical Engineering and Computer Science Ningbo UniversityNingbo 315211China College of Intelligent Systems Science and Engineering Harbin Engineering UniversityHarbin 150001China College of Mathematical Sciences Harbin Engineering UniversityHarbin 150001China

In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely *** are made to analyze the kinematic and compliance model of the robot joint with harmonic drive to acquire high precision torque *** analyzing the structures of the harmonic drive and experiment apparatus,a scheme of the proposed joint torque estimation method based on both the dynamic characteristics and unscented Kalman filter(UKF)is designed and *** on research and scheme,torque estimation methods in view of only harmonic drive compliance model and compliance model with the Kalman filter are simulated as guidance and reference to promote the research on the torque estimation ***,a promoted torque estimation method depending on both harmonic drive compliance model and UKF is designed,and simulation results compared with the measurements of a commercial torque sensor,have verified the effectiveness of the proposed method.

关键词： harmonic drive torque estimation compliance model unscented Kalman filter(UKF)

Intraspecific differences in effects of co-contamination of cadmium and arsenate on early seedling growth and metal uptake by wheat

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Journal of Environmental Sciences 2007年第10期19卷 1221-1227页

作者： LIU xiao-li ZHANG shu-zhen State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium （Cd）（0-10 mg/L） and arsenate （As（V））（0-8 mg/L） on the growth parameters and accumulation of Cd and As in six wheat varieties Jing- 9428, Duokang- 1, Jingdong- 11, Jing-411, Jingdong-8 and Zhongrnai-8. The endpoints of wheat seedlings, including seed germination, biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties （p 〈 0.05）. The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongrnai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongrnai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.

关键词： Cd As varieties co-contamination wheat seedling

EVOLUTION AND DEVELOPMENT OF GUANGZHOU-HONG KONG CORRIDOR

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Chinese Geographical Science 2005年第3期15卷 206-211页

作者： LI Ping CAO xiao-shu Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 P. R. China School of Geography and Planning Sun Yat-Sen University Guangzhou 510275 P. R. China

With its rapid development in the past two decades, the Pearl River Delta has become one of the most developed regions in China. During this period, an important corridor between Hong Kong and Guangzhou has emerged and shaped the spatial structure of the region. The growth of this region has been greatly marched with the twin poles of Guangzhou and Hong Kong, and the economic and social development has taken place in a corridor between these two metropolises. This paper provides an analysis of the significance of this corridor in terms of its infrastructure, population, land use, and economic development. Massive infrastructure construction in the corridor has played an important role in its development. The corridor has high-frequent transport, and each transport mode has contributed in a different way to the process of development of the corridor. With high land use intensity and high population density, it is developing the characteristics of a megalopolis. As a pathway of connection between Guangzhou and Hong Kong, the corridor includes not only physical infrastructure, such as roads, railways and airports, but also logistics operations, human resources, information and capital, which plays important roles in accelerating business development. It demonstrates how this Main Street has become one of the most important factors in regional development.

关键词： corridor regional development evolution

Liutex (vortex) core definition and automatic identification for turbulence vortex structures

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Journal of Hydrodynamics 2019年第5期31卷 857-863页

作者： Hongyi Xu xiao-shu Cai Chaoqun Liu Aeronautics and Astronautics Department Fudan UniversityShanghai 200433China School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Department of Mathematics University of Texas at ArlingtonArlington 76019TexasUSA

As a milestone research in vortex identification(VI),the physical quantity of Liutex,including its forms of scalar,vector and tensor,was systematically explored and rigorously obtained as the third-generation(3G)of the vortex definition and identification methods distinguished from the first generation(1G)by vorticity and the second generation(2G)by the vortex identification(VI)criteria solely dependent on the velocity gradient tensor *** on these findings,the vortex-core lines were abstracted from the well-defined Liutex,and for the first time,were automatically generated and massively visualized using *** distinctive characteristics of these vortex cores with the intriguing threshold-independency make them be the uniquely appropriate entity to represent and to depict the vortex structures in *** letter made use of the DNS data for the natural transition in a zero-pressure gradient flat-plate(Type-A turbulent boundary layer(TBL))and the fully-developed turbulence in a square annular duct(Type-B TBL)to demonstrate the vortex structure represented by the vortex-core *** 3G VI approach based on the vortex-core lines is capable of profoundly uncovering the vortex ***,the capability of automatically identifying the vortex cores and massively visualizing the large number of vortex-core behaviors in a transient way will enable the fluid-mechanics and other related-science communities to step into a new era to explore the intrinsic natures of the centennial puzzle of turbulence and other vortex-related phenomena in future.

关键词： Direct numerical simulation turbulence structure vortex core identification and automation

Coherence Resonance and Noise-Induced Synchronization in Hindmarsh-Rose Neural Network with Different Topologies

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Communications in Theoretical Physics 2007年第4X期48卷 759-762页

作者： WEI Du-Qu LUO xiao-shu College of Physics and Electronic Engineering Guangxi Normal University Guilin 541004 China

In this paper, we investigate coherence resonance （CR） and noise-induced synchronization in Hindmarsh- Rose （HR） neural network with three different types of topologies： regular, random, and small-world. It is found that the additive noise can induce CR in HR neural network with different topologies and its coherence is optimized by a proper noise level. It is also found that as coupling strength increases the plateau in the measure of coherence curve becomes broadened and the effects of network topology is more pronounced simultaneously. Moreover, we find that increasing the probability p of the network topology leads to an enhancement of noise-induced synchronization in HR neurons network.

关键词： coherence resonance small-world network synchronization Hindmarsh-Rose neural

Tuning transport coefficients of monolayer MoSi_(2)N_(4) with biaxial strain

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Chinese Physics B 2021年第6期30卷 484-489页

作者： xiao-shu Guo San-Dong Guo School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China Key Laboratory of Advanced Semiconductor Devices and Materials Xi'an University of Posts and TelecommunicationsXi'an 710121China

Experimentally synthesized MoSi_(2)N_(4)(Science 369 670(2020)) is a piezoelectric semiconductor. Here, we systematically study the large biaxial(isotropic) strain effects(0.90–1.10) on electronic structures and transport coefficients of monolayer MoSi_(2)N_(4) by density functional theory(DFT). With a/a0 from 0.90 to 1.10, the energy band gap firstly increases, and then decreases, which is due to transformation of conduction band minimum(CBM). Calculated results show that the MoSi_(2)N_(4) monolayer is mechanically stable in the considered strain range. It is found that the spin-orbital coupling(SOC) effects on Seebeck coefficient depend on the strain. In unstrained MoSi_(2)N_(4), the SOC has neglected influence on Seebeck coefficient. However, the SOC can produce important influence on Seebeck coefficient, when the strain is applied,for example, 0.96 strain. The compressive strain can change relative position and numbers of conduction band extrema(CBE), and then the strength of conduction bands convergence can be enhanced, to the benefit of n-type ZT_e. Only about0.96 strain can effectively improve n-type ZT_e. Our works imply that strain can effectively tune the electronic structures and transport coefficients of monolayer MoSi_(2)N_(4), and can motivate farther experimental exploration.

关键词： MoSi_(2)N_(4) electronic transport 2D materials

POD analysis on vortical structures in MVG wake by Liutex core line identification

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Journal of Hydrodynamics 2020年第3期32卷 497-509页

作者： Xiang-rui Dong xiao-shu Cai Yinlin Dong Chaoqun Liu School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering Shanghai 200093China Department of Mathematics University of Central ArkansasConway 72035USA Department of Mathematics University of Texas at ArlingtonArlington 76019USA

The Liutex core line method, first combined with the snapshot proper orthogonal decomposition (POD), is utilized in a supersonic micro-vortex generator (MVG) wake flow at Ma = 2.5 and Reθ = 5 760 to reveal the physical significance of each POD mode of the flow field. Compared with other scalar-based vortex identification methods, the Liutex core line identification is verified to be the most appropriate approach that is threshold-free and provides full information of a fluid rotation motion. Meanwhile, the Liutex integration is employed to quantitatively track the evolution of the vortices in MVG wake and is applied to the determination of the effective control section of the MVG wake for the optimization study of MVG design. The physical mechanism of each POD mode for multi-scale and multi-frequency vortical structures is investigated by using Liutex core line identification to give some revelations. For the mean mode (mode 0) indicating the time-averaged velocity flowfield of the MVG wake flow, a pair of primary counter-rotating streamwise vortices and another pair of secondary vortices is uniquely identified by two pairs of Liutex core lines with Liutex magnitude. In contrast, mode 1 is featured by a fluctuated roll-up motion of streamwise vortex, and the streamwise component of the MVG wake is demonstrated to be dominant in terms of the total kinetic energy contribution. Meanwhile, a dominant shedding frequency of St = 0.072 is detected from the temporal behavior of mode 2, which has the organized arc-shaped vortex structures shedding from MVG induced by the K-H instability. Additionally, mode 4 subjects to low-frequency oscillations of the wall vortices and thus takes a relatively lower frequency of St = 0.044.

关键词： Proper orthogonal decomposition(POD) vortex identification Liutex vortex core lines micro-vortex generator(MVG)

Analysis of temperature,stress,and displacement distributions of staves for a blast furnace

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International Journal of Minerals,Metallurgy and Materials 2009年第5期16卷 512-516页

作者： xiao-jun Ning shu-sen Cheng Ning-qiang Xie School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

The temperature of gas flow inside a blast furnace （BF） changes significantly when the blast furnace is under unstable operations, and the temperature and stress distributions of cooling staves （CS） for BF work the same pattern. The effect of gas temperature on the temperature, stress, and displacement distributions of the cooling stave were analyzed as the gas temperature inside the blast furnace rose from 1000 to 1600℃ in 900 s. The results show that both the temperature and temperature gradient of the hot side of CS increase when the gas flow temperature inside BF rises. The temperature gradient of the hot side of CS is greater than that of the other area of CS and it can reach 65℃/mm. In the vertical direction of the hot side of CS, closer to the central part of CS, the stress intensity is greater than that of the other area of the hot side of CS, which causes cracks on the hot side of CS in the vertical di- rection. As the gas temperature increases, the stress intensity rate near the fixed pin increases and finally reaches 45 MPa/s. Fatigues near the fixed pin and bolts are caused by great stress intensity rate and the area around the pin can be damaged easily. The edge of CS bends toward the cold side and the central part of CS shifts toward the hot surface.

关键词： blast furnace cool stave gas temperature numerical simulation

Liutex identification on hairpin vortex structures in a channel based on msfle and moving-PIV

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Journal of Hydrodynamics 2021年第6期33卷 1119-1128页

作者： Xin-ran Tang Xiang-rui Dong xiao-shu Cai Wu Zhou School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China

The spatiotemporal evolution of hairpin vortex structures in a fully developed turbulent boundary layer is investigated qualitatively and quantitatively by using two image *** this paper,the moving single-frame and long-exposure(MSFLE)image method is used to intuitively track the evolution process of a hairpin vortex,while the moving particle image velocimetry(moving-PIV)method is applied for obtaining a moving velocity field for quantitative *** to the structural characteristics of the hairpin vortex,an inclined light sheet with an appropriate inclination of 53°is arranged to capture the complete hairpin vortex structure at Re_(θ)=97–*** addition,the core size and the rotational strength of a hairpin vortex are further defined and quantified by the Liutex vector *** evolution process of a complete hairpin vortex structure observed by MSFLE shows that the shear along the normal direction leads to an increasing strength of the hairpin vortex,accompanied by a lifting vortex head and a distance decrease between two vortex legs during the dissipation *** combining moving-PIV with the Liutex identification,the spatiotemporal evolution of four typical regions of a hairpin vortex projecting into a 53°cross-section is *** results show that the process from the generation to the dissipation of a single hairpin vortex can be well characterized and recorded by the Liutex based on the core size and rotational intensity,and the evolution process is consistent with the MSFLE *** to the statistics of vortex core size and rotation intensity along time,the evolution of the hairpin vortex necks and legs can be described as a process of enhancement followed by *** the vortex head,its evolution maintains longer attributed to its far-from-wall position,which consists of an absolute enhancement process(stage 1)with an increasing rotation strength and a constant core size,and an absolute dissipation(stage 2)with a dec

关键词： Turbulent boundary layer hairpin vortex moving single-frame and long-exposure moving particle image velocimetry(PIV) Liutex vortex identification method