Computational Studies on Mesh Stiffness of Paralleled Helical Beveloid Gear Pair

Ruihua Sun,Chaosheng Song,Caichao Zhu,Yawen Wang,Xingyu Yang 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.1

Considering the asymmetrical left and right tooth profiles including the transient curve at the tooth root region and the varying thickness along the axial direction due to the cone angle, we build the accurate profile curve model including the transient curve at the tooth root of helical beveloid gear with machining parameters to solve the problem of non-applicability of real digital model. According to the feature of gear shape varying along tooth width direction, we introduced the slicing method and derived its grouping formula. Finally, the efficient and accurate slicing-based mesh stiff ness calculation model of paralleled helical beveloid gears was proposed using potential energy theory. Then, mesh stiff ness was calculated using finite element contact model for comparison and verification. Finally, the impacts of macro geometry parameters including cone angle, normal pressure angle, helix angle, tooth width and addendum coefficient on single and total mesh stiff ness were analyzed. The calculated mesh stiff ness correlates well with the results from FEM with the maximum peak error is 4.8%. Results show that the tooth width shows an obvious incremental impact on average total mesh stiff ness. When the pressure angle, helix angle, cone angle and addendum coefficient increase, the average total mesh stiff ness increases first and then decreases. For the fluctuating value, it increases as the tooth width, helix angle and cone angle increase. However, the pressure angle and addendum coefficient show an opposite impact on the fluctuating value.

In Situ Assembly of 2D Conductive Vanadium Disulfide with Graphene as a High-Sulfur-Loading Host for Lithium-Sulfur Batteries

Zhu, Xingyu,Zhao, Wen,Song, Yingze,Li, Qiucheng,Ding, Feng,Sun, Jingyu,Zhang, Li,Liu, Zhongfan Wiley (John WileySons) 2018 ADVANCED ENERGY MATERIALS Vol.8 No.20

UDE-based Nonlinear Path-following Control of Autonomous Underwater Vehicles With Multiple Uncertainties and Input Saturation

Jianming Miao,Xingyu Sun,Kankan Deng,Xi Gong,Chao Peng,Tao Liu,Haosu Zhang 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.3

This paper proposes a novel UDE-based nonlinear path-following (PF) control scheme for the underactuated autonomous underwater vehicle (AUV) with multiple uncertainties and input saturation. Firstly, to overcomethe drawback of dependence on the accurate mathematical model, the unknown time-varying sideslip angular speedin the error dynamic model is treated as kinematic uncertainty, and the linear superposition of parameter uncertainties, environmental perturbations, and other unmodeled dynamics is regarded as lumped dynamic uncertainty. Bothkinematic and dynamic uncertainties are estimated and compensated by the designed uncertainty and disturbanceestimators (UDEs). Secondly, a novel augmented backstepping controller based on the estimates generated by UDEsis proposed to achieve PF control of the underactuated AUV. The nonlinear tracking differentiator (NTD) is adoptedto prevent the “explosion of complexity” inherent in the traditional back-stepping method, and the auxiliary dynamical system is utilized to solve the issue of input saturation. Lastly, the stability analysis of the entire enclosed-loopframework is presented. Simulations and comparative analyses are presented to demonstrate the effectiveness androbustness of the presented strategy

Analysis and Design of Function Decoupling High Voltage Gain DC/DC Converter

Yuqi Wei,Quanming Luo,Xingyu Lv,Pengju Sun,Xiong Du 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

Traditional boost converters have difficulty realizing high efficiency and high voltage gain conversion due to 1) extremely large duty cycles, 2) high voltage and current stresses on devices, and 3) low conversion efficiency. Therefore, a function decoupling high voltage gain DC/DC converter composed of a DC transformer (DCX) and an auxiliary converter is proposed. The role of DCX is to realize fixed gain conversion with high efficiency, whereas the role of the auxiliary converter is to regulate the output voltage. In this study, different forms of combined high voltage gain converters are compared and analyzed, and a structure is selected for the function decoupling high voltage gain converter. Then, topologies and control strategies for the DCX and auxiliary converter are discussed. On the basis of the discussion, an optimal design method for circuit parameters is proposed, and design procedures for the DCX are described in detail. Finally, a 400 W experimental prototype based on the proposed optimal design method is built to verify the accuracy of the theoretical analysis. The measured maximum conversion efficiency at rated power is 95.56%.

A Learning Control Strategy for Robot-assisted Bathing via Impedance Sliding Mode Technique With Non-repetitive Tasks

Yuexuan Xu,Xin Guo,Bokai Xuan,Hao Sun,Gaowei Zhang,Jian Li,Xingyu Huo,Zhifeng Gu 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.3

This paper investigates an impedance-based iterative learning sliding mode control scheme for robotassisted bathing, taking into consideration scenarios with unknown model parameters. Initially, the utilization ofimpedance control is not confined to merely adjusting the desired trajectory but is also instrumental in ensuringactive compliance control during the robot-assisted bathing procedure. Furthermore, an iterative learning control(ILC) is devised to estimate the iteration-invariant dynamic parameters, which are intricate and challenging to precisely ascertain in practical applications. To mitigate the effect of divergent initial conditions in ILC, a trajectoryreconstruction method is introduced, thus ensuring the convergence of tracking errors even when starting from random initial states. Moreover, an adaptive sliding mode control mechanism is proposed to counteract non-parametricexternal disturbances and the torque generated through human-machine interaction during the bathing process. Theconvergence of the double closed-loop system in both the time and iterative domains is demonstrated through theapplication of the composite energy function method. Eventually, the efficacy and superiority of the control strategyoutlined in this paper are jointly verified through co-simulation employing MATLAB and ADAMS.

Vanadium Dioxide-Graphene Composite with Ultrafast Anchoring Behavior of Polysulfides for Lithium-Sulfur Batteries

Song, Yingze,Zhao, Wen,Zhu, Xingyu,Zhang, Li,Li, Qiucheng,Ding, Feng,Liu, Zhongfan,Sun, Jingyu American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.18

<P>The lithium-sulfur (Li-S) battery has been deemed as one of the most promising energy-storage systems owing to its high energy density, low cost, and environmental benignancy. However, the capacity decay and kinetic sluggishness stemming from polysulfide shuttle effects have by far posed a great challenge to practical performance. We herein demonstrate the employment of low-cost, wet-chemistry-derived VO<SUB>2</SUB> nanobelts as the effective host additives for the graphene-based sulfur cathode. The VO<SUB>2</SUB> nanobelts displayed an ultrafast anchoring behavior of polysulfides, managing to completely decolor the polysulfide solution in 50 s. Such a fast and strong anchoring ability of VO<SUB>2</SUB> was further investigated and verified by experimental and theoretical investigations. Benefitting from the synergistic effect exerted by VO<SUB>2</SUB> in terms of chemical confinement and catalytic conversion of polysulfides, the Li-S batteries incorporating VO<SUB>2</SUB> and graphene manifested excellent cycling and rate performances. Notably, the batteries delivered an initial discharge capacity of 1405 mAh g<SUP>-1</SUP> when cycling at 0.2 C, showed an advanced rate performance of ∼830 mAh g<SUP>-1</SUP> at 2 C, and maintained a stable cycling performance at high current densities of 1, 2, and 5 C over 200 cycles, paving a practical route toward cost-effective and environmentally benign cathode design for high-energy Li-S batteries.</P> [FIG OMISSION]</BR>

Analysis and Design of Function Decoupling High Voltage Gain DC/DC Converter

Wei, Yuqi,Luo, Quanming,Lv, Xingyu,Sun, Pengju,Du, Xiong The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

Traditional boost converters have difficulty realizing high efficiency and high voltage gain conversion due to 1) extremely large duty cycles, 2) high voltage and current stresses on devices, and 3) low conversion efficiency. Therefore, a function decoupling high voltage gain DC/DC converter composed of a DC transformer (DCX) and an auxiliary converter is proposed. The role of DCX is to realize fixed gain conversion with high efficiency, whereas the role of the auxiliary converter is to regulate the output voltage. In this study, different forms of combined high voltage gain converters are compared and analyzed, and a structure is selected for the function decoupling high voltage gain converter. Then, topologies and control strategies for the DCX and auxiliary converter are discussed. On the basis of the discussion, an optimal design method for circuit parameters is proposed, and design procedures for the DCX are described in detail. Finally, a 400 W experimental prototype based on the proposed optimal design method is built to verify the accuracy of the theoretical analysis. The measured maximum conversion efficiency at rated power is 95.56%.

90-fs diode-pumped Yb:CLNGG laser mode-locked using single-walled carbon nanotube saturable absorber.

Zhang, Yuangeng,Petrov, Valentin,Griebner, Uwe,Zhang, Xingyu,Choi, Sun Young,Gwak, Ji Yoon,Rotermund, Fabian,Mateos, Xavier,Yu, Haohai,Zhang, Huaijin,Liu, Junhai Optical Society of America 2014 Optics express Vol.22 No.5

<P>A diode-pumped Yb:CLNGG laser is mode-locked with a single-walled carbon nanotube saturable absorber (SWCNT-SA) for the first time. Pulse durations as short as 90 fs are obtained at ~1049 nm with 0.4% output coupler, the shortest pulses to our knowledge for a diode-pumped 1-?m laser applying SWCNTs as saturable absorber. Using 3% output coupler, the maximum average output power reached 90 mW at a repetition frequency of 83 MHz.</P>

Synchronous immobilization and conversion of polysulfides on a VO₂-VN binary host targeting high sulfur load Li-S batteries

Song, Yingze,Zhao, Wen,Kong, Long,Zhang, Li,Zhu, Xingyu,Shao, Yuanlong,Ding, Feng,Zhang, Qiang,Sun, Jingyu,Liu, Zhongfan The Royal Society of Chemistry 2018 ENERGY AND ENVIRONMENTAL SCIENCE Vol.11 No.9

<P>Lithium-sulfur (Li-S) batteries are deemed as one of the most promising next-generation energy storage systems. However, their practical application is hindered by existing drawbacks such as poor cycling life and low Coulombic efficiency due to the shuttle effect of lithium polysulfides (LiPSs). We herein present an <I>in situ</I> constructed VO2-VN binary host which combines the merits of ultrafast anchoring (VO2) with electronic conducting (VN) to accomplish smooth immobilization-diffusion-conversion of LiPSs. Such synchronous advantages have effectively alleviated the polysulfide shuttling, promoted the redox kinetics, and hence improved the electrochemical performance of Li-S batteries. As a result, the sulfur cathode based on the VO2-VN/graphene host exhibited an impressive rate capability with ∼1105 and 935 mA h g<SUP>−1</SUP> at 1C and 2C, respectively, and maintained long-term cyclability with a low capacity decay of 0.06% per cycle within 800 cycles at 2C. More remarkably, favorable cyclic stability can be attained with a high sulfur loading (13.2 mg cm<SUP>−2</SUP>). Even at an elevated temperature (50 °C), the cathodes still delivered superior rate capacity. Our work emphasizes the importance of immobilization-diffusion-conversion of LiPSs toward the rational design of high-load and long-life Li-S batteries.</P>

Microfluidic Synthesis of Hybrid Nanoparticles with Controlled Lipid Layers: Understanding Flexibility-Regulated Cell–Nanoparticle Interaction

Zhang, Lu,Feng, Qiang,Wang, Jiuling,Zhang, Shuai,Ding, Baoquan,Wei, Yujie,Dong, Mingdong,Ryu, Ji-Young,Yoon, Tae-Young,Shi, Xinghua,Sun, Jiashu,Jiang, Xingyu American Chemical Society 2015 ACS NANO Vol.9 No.10

<P>The functionalized lipid shell of hybrid nanoparticles plays an important role for improving their biocompatibility and <I>in vivo</I> stability. Yet few efforts have been made to critically examine the shell structure of nanoparticles and its effect on cell–particle interaction. Here we develop a microfluidic chip allowing for the synthesis of structurally well-defined lipid-polymer nanoparticles of the same sizes, but covered with either lipid-monolayer-shell (MPs, monolayer nanoparticles) or lipid-bilayer-shell (BPs, bilayer nanoparticles). Atomic force microscope and atomistic simulations reveal that MPs have a lower flexibility than BPs, resulting in a more efficient cellular uptake and thus anticancer effect than BPs do. This flexibility-regulated cell–particle interaction may have important implications for designing drug nanocarriers.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-10/acsnano.5b05792/production/images/medium/nn-2015-05792e_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b05792'>ACS Electronic Supporting Info</A></P>