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Smart Gait:A Gait Optimization Framework for Hexapod Robots

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 146-159页

作者： Yunpeng yin feng Gao Qiao sun Yue Zhao Yuguang Xiao State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Lenovo Corporation ShanghaiChina AI Institute School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The current gait planning for legged robots is mostly based on human presets,which cannot match the flexible characteristics of natural mammals.This paper proposes a gait optimization framework for hexapod robots called Smart Gait.Smart Gait contains three modules:swing leg trajectory optimization,gait period&duty optimization,and gait sequence optimization.The full dynamics of a single leg,and the centroid dynamics of the overall robot are considered in the respective modules.The Smart Gait not only helps the robot to decrease the energy consumption when in locomotion,mostly,it enables the hexapod robot to determine its gait pattern transitions based on its current state,instead of repeating the formalistic clock-set step cycles.Our Smart Gait framework allows the hexapod robot to behave nimbly as a living animal when in 3D movements for the first time.The Smart Gait framework combines offline and online optimizations without any fussy data-driven training procedures,and it can run efficiently on board in real-time after deployment.Various experiments are carried out on the hexapod robot LittleStrong.The results show that the energy consumption is reduced by 15.9%when in locomotion.Adaptive gait patterns can be generated spontaneously both in regular and challenge environments,and when facing external interferences.

关键词： Gait optimization Swing trajectory optimization Legged robot Hexapod robot

Landing control method of a lightweight four-legged landing and walking robot

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Frontiers of Mechanical Engineering 2022年第4期17卷 33-52页

作者： Ke yin Chenkun QI Yue GAO Qiao sun feng GAO School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The prober with an immovable lander and a movable rover is commonly used to explore the Moon’s surface.The rover can complete the detection on relatively flat terrain of the lunar surface well,but its detection efficiency on deep craters and mountains is relatively low due to the difficulties of reaching such places.A lightweight four-legged landing and walking robot called“FLLWR”is designed in this study.It can take off and land repeatedly between any two sites wherever on deep craters,mountains or other challenging landforms that are difficult to reach by direct ground movement.The robot integrates the functions of a lander and a rover,including folding,deploying,repetitive landing,and walking.A landing control method via compliance control is proposed to solve the critical problem of impact energy dissipation to realize buffer landing.Repetitive landing experiments on a five-degree-of-freedom lunar gravity testing platform are performed.Under the landing conditions with a vertical velocity of 2.1 m/s and a loading weight of 140 kg,the torque safety margin is 10.3%and 16.7%,and the height safety margin is 36.4%and 50.1%for the cases with or without an additional horizontal disturbance velocity of 0.4 m/s,respectively.The study provides a novel insight into the next-generation lunar exploration equipment.

关键词： landing and walking robot lunar exploration buffer landing compliance control

Hyperelastic Graphene Aerogels Reinforced by In‑suit Welding Polyimide Nano Fiber with Leaf Skeleton Structure and Adjustable Thermal Conductivity for Morphology and Temperature Sensing

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Advanced Fiber Materials 2023年第3期5卷 1037-1049页

作者： Weida yin Mengmeng Qin Huitao Yu Jinxu sun Wei feng School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin 300350People’s Republic of China

Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors.However,graphene sheets are prone to slips under repeated compression due to inadequate chemical con-nections.In addition,the heat-transfer performance of existing compression strain sensors under stress is unclear and lacks research,making it difficult to perform real-temperature detections.To address these issues,a hyperelastic polyimide fiber/graphene aerogel(PINF/GA)with a three-dimensional interconnected structure was fabricated by simple one-pot compound-ing and in-situ welding methods.The welding of fiber lap joints promotes in-suit formation of three-dimensional crosslinked networks of polyimide fibers,which can effectively avoid slidings between fibers to form reinforced ribs,preventing graphene from damage during compression.In particular,the inner core of the fiber maintains its macromolecular chain structure and toughness during welding.Thus,PINF/GA has good structural stabilities under a large strain compression(99%).Moreover,the thermal and electrical conductivities of PINF/GA could not only change with various stresses and strains but also keep the change steady at specific stresses and strains,with its thermal-conductivity change ratio reaching up to 9.8.Hyperelastic PINF/GA,with dynamically stable thermal and electrical conductivity,as well as high heat tolerance,shows broad applica-tion prospects as sensors in detecting the shapes and temperatures of unknown objects in extreme environments.

关键词： Graphene aerogel Fiber welding Highly compressible High and low temperature resistance Cyclic stability Flexible tactile sensor

One-pot synthesis of hexagonal NaLuF_(4):Yb,Er microcrystals with enhanced upconversion emission and high production yield

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Journal of Rare Earths 2023年第4期41卷 498-506页

作者： Xuesong Zhai yin Li Wei Zhao Wu sun Meng He Jing feng School of Materials Science and Engineering Yancheng Institute of TechnologyYancheng 224051China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

In this work,monodisperseβ-NaLuF_(4):Yb,Er microcrystals with intense upconversion emission were synthesized via a modified hydrothermal method.With the increase of reactant concentration,their production yield is increased obviously,and the upconversion emission intensity inβ-NaLuF_(4):Yb,Er microcrystals is also enhanced significantly.The luminescence enhancement should be attributed to minimal internal OH defects,validated by a combination of analytical X-ray diffraction(XRD),energy dispersive spectrum(EDS),and Eu^(3+)structural probe measurements.We also reveal that high Na^(+):RE~(3+)ratio in theβ-NaLuF_(4):Yb,Er microcrystals prepared under Na^(~)+-rich reaction will arouse the increased repulsive energy ofβ-NaLuF_(4)microcrystals between F^(~)-and OH^(~)-anions and then facilitate the substitution of large OH^(-)ions by small F^(~)-ions under F^(~)--rich reaction conditions.Minimal OH^(-)concentrations can limit nonradiative relaxation and promote excitation energy harvesting for high upconversion efficiency.The presented results not only offer a facile method for the simultaneous production yield and luminescence intensity increase ofβ-NaREF_(4)microcrystals,but also uncover a better insight into the upconversion emission alterations,which is favorable to broaden their practical applications.

关键词： β-NaLuF_(4):Yb Er microcrystals Upconversion High reactant concentration Luminescence enhancement Internal OH~-defects High production yield

Terrain classification and adaptive locomotion for a hexapod robot Qingzhui

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Frontiers of Mechanical Engineering 2021年第2期16卷 271-284页

作者： Yue ZHAO feng GAO Qiao sun Yunpeng yin State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Legged robots have potential advantages in mobility compared with wheeled robots in outdoor environments. The knowledge of various ground properties and adaptive locomotion based on different surface materials plays an important role in improving the stability of legged robots. A terrain classification and adaptive locomotion method for a hexapod robot named Qingzhui is proposed in this paper. First, a force-based terrain classification method is suggested. Ground contact force is calculated by collecting joint torques and inertial measurement unit information. Ground substrates are classified with the feature vector extracted from the collected data using the support vector machine algorithm. Then, an adaptive locomotion on different ground properties is proposed. The dynamic alternating tripod trotting gait is developed to control the robot, and the parameters of active compliance control change with the terrain. Finally, the method is integrated on a hexapod robot and tested by real experiments. Our method is shown effective for the hexapod robot to walk on concrete, wood, grass, and foam. The strategies and experimental results can be a valuable reference for other legged robots applied in outdoor environments.

关键词： terrain classification hexapod robot legged robot adaptive locomotion gait control

Peptidoglycan inhibits beigeing of adipose tissue

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Acta Pharmaceutica Sinica B 2022年第2期12卷 990-993页

作者： Hong Chen Lijun sun Lu feng Michael Mulholland Weizhen Zhang Yue yin Department of Physiology and Pathophysiology School of Basic Medical SciencesKey Laboratory of Molecular Cardiovascular ScienceMinistry of EducationPeking UniversityBeijing 100191China Department of Surgery University of Michigan Medical CenterAnn ArborMI 48109-0346USA

To the Editor:Obesity, an epidemic metabolic disease characterized by excessive fat accumulation, causes a significant economic burden on families and the society. The discovery of beige adipocytes has provided us with a brand new approach for the intervention of obesity^(1). Beige adipocytes increase energy expenditure and improve the balance of glucose and lipid metabolism. Reduction of beige adipocytes is a hallmark of obesity. Mechanism underlying the decrement of beigeing remains largely unknown.

关键词： Beige adipocytes Brown adipocytes Obesity Metabolic inflammation

Therapeutic effect of oridonin on mice with prostate cancer

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Asian Pacific Journal of Tropical Medicine 2016年第2期9卷 182-185页

作者： Ming Ming Feng-Yin Sun Wen-Tong Zhang Ji-Ke Liu Department of Pediatric Surgery Qilu Hospital of Shandong University Department of Pediatric Surgery Taian City Central Hospital Department of Pediatric Surgery Liaocheng Hospital

Objective: To investigate the therapeutic effect and the related mechanism of oridonin on mice with prostate cancer. Methods: Sixty BALB/C male nude mice were selected. A model of RM-1 cell transplantation tumor of prostate cancer was built by the subcutaneous inoculation of RM-1 cells. After that, those 60 experimental mice were randomly divided into groups A, B and C. Each group had 20 mice. Mice in group A were treated with 0.2 m L of normal saline(0.9%) by intraperitoneal injection once a day; mice in group B received intraperitoneal injection of 1.875 mg/m L of oridonin once a day; and mice in group C received intraperitoneal injection of 7.5 mg/m L of oridonin once a day. Mice in the three groups were treated uninterruptedly for 5 weeks and were all killed. Then, tumors were excised and weighed to calculate their growth inhibitory rate, volume increment and anti-tumor rate. Thymus and spleen of mice in the three groups were collected to calculate the thymus and spleen index. Immunohistochemical staining was applied to observe the expression of caspase-3 in prostate cancer tissue of mice of the three groups. Results: The qualities and volume increment of tumors in groups B and C were significantly lower than those of group A(P 0.05). Immumohistochemical staining revealed that the caspase-3 protein in prostate cancer tissue of mice of group A expressed negatively with colourless or light-colored karyon; while the caspase-3 protein in prostate cancer tissue of mice of group B expressed positively with dark-colored karyon, centralized distribution and granular sensation; a

关键词： Oridonin Prostate cancer RM-1 cells Caspase-3

Insights into spin polarization regulated exciton dissociation and charge separation of C_(3)N_(4)for efficient hydrogen evolution and simultaneous benzylamine oxidation

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Nano Research 2023年第7期16卷 8845-8852页

作者： Gen Li Xiaomei sun Peng Chen Meiyang Song Tianxiang Zhao Fei Liu Shuang-feng yin Provincial Guizhou Key Laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China College of Chemistry and Chemical Engineering Advanced Catalytic Engineering Research Center of the Ministry of EducationState Key Laboratory of Chemo/Biosensing and ChemometricsHunan UniversityChangsha 410082China

The employment of spin polarization under an external magnetic field holds great potential for the improvements of photocatalytic performance.However,owing to the huge difference in dielectric properties between ferromagnetic oxide and polymers,the photogenerated excitons with spin states are often limited to the ferromagnetic oxide wells,which leads to unsatisfactory activity.In this paper,a single-atom Co-doped C_(3)N_(4)photocatalyst is successfully synthesized for photocatalytic water splitting and simultaneous oxidation of benzylamine.Under a tiny external magnetic field(24.5 mT),the hydrogen production rate could reach at 3979.0μmol·g^(-1)·h^(-1),which is about 340 times that of C_(3)N_(4).Experimental results and theoretical calculations indicate that the interaction of Co d and N p orbital changes the symmetry center of C_(3)N_(4),resulting in an increase in dielectric constant and spin polarization.Moreover,magnetic fields further promote parallel electron spin,and the increased number of charges with the parallel spin-down state is likely to dissociate under the action of an external magnetic field.On the other hand,the Co-N bond provides a huge built-in electric field and active site for strengthening the charge transfer and surface reaction.This work not only deepens the understanding of spin polarization,but also enriches methods to accelerate electron-hole separation.

关键词： low magnetic field C_(3)N_(4) spin polarization photocatalytic hydrogen evolution benzylamine oxidation

Stabilization technology and corrosion mechanism of rust layer on Q370 weathering steel surface

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Journal of Iron and Steel Research(International) 2022年第10期29卷 1694-1709页

作者： Shao-zheng Ma Li-juan sun Hu-yuan sun Hong-bin sun Jin-feng Jiang Yi-xin yin Shu-feng Qu Zhen-hua Liu Shao-xia Xu Key Laboratory of Marine Environmental Corrosion and Bio-Fouling Institute of OceanologyChinese Academy of SciencesQingdao266071ShandongChina University of Chinese Academy of Sciences Beijing100049China Open Studio for Marine Corrosion and Protection Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao266237ShandongChina Shandong Weilai High Speed Railway Co. Ltd.Jinan250102ShandongChina School of Civil Engineering Shandong UniversityJinan250061ShandongChina China Railway No.10 Engineering Group Co. Ltd.Qingdao266034ShandongChina

A newly developed rust layer on Q370qENH weathering steel(sample C)was studied under dry–wet cycle test of 3.5 wt.%NaCl solution and salt spray test,compared with the bare weathering steel(sample A)and the weathering steel with additive contents(CuSO_(4)0.2,FeSO_(4)0.1,NaHSO_(3)0.02,NaCl 0.02,Na_(2)HPO_(4)0.01,and water balance,in mass%,termed as sample B).Corrosion mechanism of Q370qENH weathering steel after different surface treatments was investigated by means of surface potential scanning,mass change,polarization curve,and X-ray diffraction.The results of X-ray diffraction indicate that rust of bare weathering steel has rare Fe_(3)O_(4),and a dense oxide layer mainly composed of Fe_(3)O_(4) is formed on rust of both sample B and sample C.The surface potential of sample A gradually increases to−0.2 V in the dry–wet cycle test,while the surface potential of sample A maintains at about−0.6 V in the salt spray test.The surface potential of sample B and sample C is higher than that of sample A in the early stage and remains stable during the short-term accelerated corrosion test.Moreover,the mass change of sample C gradually stabilizes with time in the dry–wet cycle and salt spray test.The corrosion current of the sample A is lower than that of sample C in the initial stage of short-term accelerated corrosion test.However,the corrosion current of sample C is smaller than that of the sample A in the experiment.The main components of the deep rust of sample A areγ-FeOOH andα-FeOOH,while those of the deep rust of sample B and sample C are Fe_(3)O_(4).

关键词： Weathering steel Rust layer stabilization Surface treatment Corrosion Surface potential scanning Rust layer analysis