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Trot Gait Design and CPG Method for a Quadruped Robot

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Journal of Bionic Engineering 2014年第1期11卷 18-25页

作者： Jiaqi Zhang Feng Gao xiaolei han Xianbao Chen Xueying han School of Mechanical Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 P. R. China State Key Laboratory of Mechanical System and Vibration 800 Dongchuan Road Shanghai 200240 P. R. China Ecology Evolution and Marine Biology University of California at Santa Barbara CA 93106 USA

Developing efficient walking gaits for quadruped robots has intrigued investigators for years. Trot gait, as a fast locomotion gait, has been widely used in robot control. This paper follows the idea of the six determinants of gait and designs a trot gait for a parallel-leg quadruped robot, Baby Elephant. The walking period and step length are set as constants to maintain a relatively fast speed while changing different foot trajectories to test walking quality. Experiments show that kicking leg back improves body stability. Then, a steady and smooth trot gait is designed. Furthermore, inspired by Central Pattern Generators （CPG）, a series CPG model is proposed to achieve robust and dynamic trot gait. It is generally believed that CPG is capable of producing rhythmic movements, such as swimming, walking, and flying, even when isolated from brain and sensory inputs. The proposed CPG model, inspired by the series concept, can automatically learn the previous well-designed trot gait and reproduce it, and has the ability to change its walking frequency online as well. Experiments are done in real world to verify this method.

关键词： quadruped robot trot gait series CPG model foot trajectory

Experimental study on the shear behavior of the interface between cushion materials and the concrete raft

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Earthquake Engineering and Engineering Vibration 2018年第1期17卷 165-178页

作者： Li Yaokun han xiaolei Khaled Galal Ji Jing State Key Laboratory of Subtropical Building Science South China University of Technology Department of Building Civil and Environmental EngineeringConcordia University

Cushion is a layer of granular materials between the raft and the ground. The shear behavior of the interface between the cushion and the raft may influence the seismic performance of the superstructure. In order to quantify such influences, horizontal shear tests on the interfaces between different cushion materials and concrete raft under monotonic and cyclic loading were carried out. The vertical pressure P_v, material type and cushion thickness h_c were taken as variables. Conclusions include： 1） under monotonic loading, P_v is the most significant factor; the shear resistance P_（hmax） increases as P_v increases, but the normalized factor of resistance μ_n has an opposite tendency; 2） for the materials used in this study, μ_n varies from 0.40 to 0.70, the interface friction angle δ_s varies from 20° to 35°, while u_（max） varies from 3 mm to 15 mm; 3） under cyclic loading, the interface behavior can be abstracted as a ＂three-segment＂ back-bone curve, the main parameters include μ_n, the displacement u_1 and stiffness K_1 of the elastic stage, the displacement u_2 and stiffness K_2 of the plastic stage; 4） by observation and statistical analysis, the significance of different factors, together with values of K_1, K_2 and μ_n have been obtained.

关键词： cushion/raft interface shear behavior monotonic test cyclic test "three-segment" back-bone curve

Microstructural investigation of Nd-rich phase in sintered Nd-Fe-B magnets through electron microscopy

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Journal of Rare Earths 2013年第8期31卷 765-771页

作者： FU Xin han xiaolei DU Zhiwei FENG Haibo LI Yanfeng National Center of Analysis and Testing for Non-ferrous Metals & Electronic Materials General Research Institute for Nonferrous Metals Beijing 100088 China Division of Functional Materials Central Iron and Steel Research Institute Beijing 100081 China

The distribution, morphologies and structures of intergranular Nd-rich phase in sintered Nd-Fe-B magnets were studied through electron microscopy. Backscattered electron （BSE） imaging revealed that Nd-rich particles with various morphologies and sizes were randomly distributed at the grain boundaries and the triple junctions of the tetragonal Nd2FelnB matrix. Through selected area electron diffraction （SAED） analysis under a systematic tilting condition, most intergranular Nd-rich phase particles, with sizes ranging from hundreds of nanometres to several micrometres, were identified as face-centred cubic （FCC） structure. Such particles possessed several approximate orientation relationships with their adjacent Nd2FelaB matrix grains, such as （002）Nd2Fe14B/ （200）FCC_Nd-rieh [120] Nd2Fe14B//[001]FCC Nd-fich, （002）Nd2Fe14B//（220）FCC_Nd-rich [110] Nd2Fe14B//[l12]FCC_Nd-rich, as well as （011）Nd2Fe14B// （13 1 ）rcc Nd-rich [111 ] Nd2Fe14B//[ 114]FCC Nd_rich, which could be attributed to minimising interracial energy. The combination of high- resolution electron microscopy with energy-dispersive X-ray spectroscopy revealed the internal inhomogeneous nature of Nd-rich phases. The large lattice distortion and nanoscale-ordered structures within a single Nd2rich grain were observed.

关键词： Nd-rich phases Nd-Fe-B magnets electron microscopy rare earths

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一种轻量级混凝土裂缝识别网络

青岛科技大学学报(自然科学版) 2025年第1期46卷 144-150页

作者：潘澳韩笑蕾赵佰亭安徽理工大学电气与信息工程学院安徽淮南232001 上海商学院物联网工程系上海201400

旨在为混凝土裂缝的类型识别提供一种有效的解决方案,为破损评估提供有力依据。针对现有经典分类网络模型存在参数量大和分类精度不足等问题,提出了一种面向嵌入式平台的轻量化PED-CNN分类算法。算法首先采用空洞卷积扩大模型的感受野,... 详细信息

旨在为混凝土裂缝的类型识别提供一种有效的解决方案,为破损评估提供有力依据。针对现有经典分类网络模型存在参数量大和分类精度不足等问题,提出了一种面向嵌入式平台的轻量化PED-CNN分类算法。算法首先采用空洞卷积扩大模型的感受野,以捕获上下文信息;其次,通过混合池化模块提取裂缝的线性特征;最后,结合部分卷积、普通卷积、深度可分离卷积和ECA注意力机制,设计了一种轻量化PED模块。实验结果表明,所提出的裂缝识别模型以0.76 M的参数,在分类准确率上达到了96.41%,实现了混凝土裂缝的高精度、高效率、智能化的识别与分类。此外,在Jetson Nano嵌入式平台上,该模型峰值帧率高达19.67 Hz,具有较强的研究价值和广泛的应用前景。

关键词：裂缝识别分类算法轻量级嵌入式平台

PERFORMANCE ANALYSIS OF AZIMUTH ELECTRONIC BEAM STEERING MODE SPACEBORNE SAR

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Journal of Electronics(China) 2013年第3期30卷 213-221页

作者： han Xiaodong Xu Wei han xiaolei Institute of Electronics Chinese Academy of Sciences University of Chinese Academy of Science

Pointing angle and pattern of the antenna can be changed swiftly to actualize the azimuth beam scanning by using electronic beam steering, which makes the Synthetic Aperture Radar (SAR) system more flexible and achieve a high resolution or cover a long strip within short time span. When the pointing angle is steered away from boresight, some aberrations may appear on the antenna pattern, e.g., the grating lobe appears, the main lobe gain decrease, and antenna pattern broadens, e.g., the aberrations result in the worsening of system performance, and complicate the corresponding performance analysis method. Conventional computation methods of performance parameters do not account for the rapid change of the antenna pattern. It introduces remarkable errors when the scanning angle is large. In this paper, a method of calculating performance parameters is proposed for the beam steering mode, which achieves the parameters by the energy accumulation in time domain. Actually, the proposed method simulates the working process of SAR and obtains accurate performance parameters. Furthermore, we analyze the effects of the grating lobe on the Azimuth Ambiguity to Signal Ratio (AASR), and present the generic Pulse Repetition Frequency (PRF) choosing principle which can also prevent the ambiguous area from weighting by the grating lobe. Finally, the effect of the antenna configuration on the performance parameters is analyzed by a system example.

关键词： Synthetic Aperture Radar(SAR) ,Azimuth beam steering ,Electronic steering ,Grating lobe ,Azimuth Ambiguity to Signal Ratio(AASR)

Numerical simulation on the seismic absorption effect of the cushion in rigid-pile composite foundation

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Earthquake Engineering and Engineering Vibration 2016年第2期15卷 369-378页

作者： han xiaolei Li Yaokun Ji Jing Ying Junhao Li Weichen Dai Baicheng School of Civil Engineering and Transportation South China University of Technology Guangzhou 510641 China State Key Laboratory of Subtropical Building Science South China University of Technology Guangzhou 510641 China Yangjiang Power Supply Bureau of China Southern Power Grid Yangjiang Guangdong 529500 China

In order to quantitatively study the seismic absorption effect of the cushion on a superstructure, a numerical simulation and parametric study are carried out on the overall FEA model of a rigid-pile composite foundation in ABAQUS. A simulation of a shaking table test on a rigid mass block is first completed with ABAQUS and EERA, and the effectiveness of the Drucker-Prager constitutive model and the finite-infinite element coupling method is proved. Dynamic time-history analysis of the overall model under frequent and rare earthquakes is carried out using seismic waves from the El Centro, Kobe, and Bonds earthquakes. The different responses of rigid-pile composite foundations and pile-raft foundations are discussed. Furthermore, the influence of thickness and modulus of cushion, and ground acceleration on the seismic absorption effect of the cushion are analyzed. The results show that： 1） the seismic absorption effect of a cushion is good under rare earthquakes, with an absorption ratio of about 0.85; and 2） the seismic absorption effect is strongly affected by cushion thickness and ground acceleration.

关键词： acceleration shaking foundations rigid quantitatively completed modulus Prager Drucker thick

Comparative transcriptome analysis reveals key genes and pathways in response to Alternaria alternata apple pathotype infection

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Horticultural Plant Journal 2024年第3期10卷 641-656页

作者： Kai Liu Zhaolin Liang An Yang Jiadi Yan Peihua Cong xiaolei han Caixia Zhang Key Laboratory of Horticultural Crop Germplasm Utilization of the Ministry of Agriculture and Rural Affairs(MOA) Research Institute of PomologyChinese Academy of Agricultural SciencesXingchengLiaoning 125100China

Apple leaf spot,caused by the Alternaria alternata apple pathotype(AAAP),is an important fungal disease of *** understand the molecular basis of resistance and pathogenesis in apple leaf spot,the transcriptomes of two apple cultivars‘hanfu'(HF)(resistant)and‘Golden Delicious'(GD)(susceptible)were analyzed at 0,6,18,24 and 48 h after AAAP inoculation by *** each time point,a large number of significantly differentially expressed genes(DEGs)were screened between AAAP-inoculated and uninoculated apple *** of the common DEGs at four time points revealed significant differences in the resistance of‘HF'and‘GD'apple to AAAP ***,RNL,and JA signal-related genes were upregulated in both cultivars to restrict AAAP ***,genes encoding CNLs,TNLs,WRKYs,and AP2s were only activated in‘HF'as part of the resistance response,of which,some play major roles in the regulation of ET and SA signal *** analysis showed that many DEGs with opposite expression trends in the two hosts may play important regulatory roles in response to AAAP *** expression of one such gene MdERF110 in‘GD'apple leaves improved AAAP ***,this study highlights the reasons for differential resistance to AAAP infection between‘HF'and‘GD'apples which can theoretically assist the molecular breeding of disease-resistant apple crops.

关键词： Apple Transcriptome Alternaria alternata apple pathotype Infection Defense response

MdAIL5 overexpression promotes apple adventitious shoot regeneration by regulating hormone signaling and activating the expression of shoot development-related genes

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Horticulture Research 2023年第11期10卷 45-58页

作者： Kai Liu An Yang Jiadi Yan Zhaolin Liang Gaopeng Yuan Peihua Cong Liyi Zhang xiaolei han Caixia Zhang Apple Breeding Chinese Academy of Agricultural Sciences Research Institute of PomologyXingcheng 125100China Key Laboratory of Horticultural Crops Germplasm Resources Utilization Ministry of Agriculture and Rural Affairs of the People’s Republic of ChinaXingcheng 125100China Shandong Academy of Grape Shandong Academy of Agricultural SciencesJinan 250100China Zhengzhou Fruit Research Institute Chinese Academy of Agricultural SciencesZhengzhou 450009China

Adventitious shoot(AS)regeneration is a significant factor in the genetic transformation of horticultural *** is also a noteworthy approach to their vegetative *** regeneration remains highly dependent on the genotype or maturity of *** here found that the AS regeneration abilities of apple leaves were positively correlated with MdAIL5 ***5 overexpression dramatically increased AS regeneration ***,MdAIL5 overexpression could restore the AS formation ability of explants to a certain extent,which was lost with an increase in *** hormone detection revealed that MdAIL5 overexpression changed the contents of auxin,cytokinin(CK),and other hormones in apple *** analysis revealed that many genes related to auxin,CK,and brassinolide signaling pathways were significantly and differentially expressed between MdAIL5-overexpressing transgenic apple and wild-type apple *** one-hybrid assays,the electrophoretic mobility shift assay,and the dual-luciferase reporter assay revealed that MdAIL5 directly binds to MdARF9 and MdHB14 promoters and positively affects their *** here established a model of MdAIL5 regulating AS formation,which acts as a theoretical basis for facilitating genotype-or explant maturity-independent AS regeneration in the future.

关键词： expression maturity regeneration

Enhancing strength and ductility in back extruded WE71 magnesium alloy cylindrical parts by introduction of multi-direction forging process

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Journal of Rare Earths 2023年第3期41卷 462-470,I0006页

作者： Dehao Bu Ting Li xiaolei han Zhiwei Du Jiawei Yuan Kui Zhang Yongjun Li Yonggang Peng Zheng Pang Chunlei Zhao National Center of Analysis and Testing for Nonferrous Metals and Electronic Materials GRINM Group Co.Ltd.Beijing 100088China Guobiao(Beijing)Testing&Certification Co. Ltd.China United Test&Certification Co.Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China State Key Laboratory for Fabrication and Processing of Non-Ferrous Metals GRIMAT Engineering Institute Co.Ltd.Beijing 101407China Gaona Aero Material Co. Ltd.Beijing 100081China

Magnesium cylindrical parts have relatively poor mechanical properties and distinct anisotropy of microstructure,which hinder their application as structural *** improve the performance of WE71 cylindrical parts,multi-direction forging(MDF)was introduced before back extrusion,and the microstructure and mechanical properties were *** of microstructure show that the grain size in the outer of the cylindrical bottom is refined from 30.1 to 27.7μm,the micro structure is more uniform and the dislocation density is *** bimodal grain structure is formed in the outer of the cylindrical wall,which is ascribed to the formation of MgsRE phases along grain *** phases result in the Zener pinning effect on grain boundaries and the reduction of DRX volume *** texture type of the cylindrical bottom is‖ED and the cylindrical wall is‖ED,and the maximum pole intensity is 1.986 and 1.664,*** of the tensile test at room temperature show that combined improved strength and ductility of the cylindrical part is attained after introducing the MDF *** ultimate tensile strength(UTS),yield strength(YS)and elongation are279 MPa,185 MPa and 12%at the bottom and 299 MPa,212 MPa and 20%at the wall.

关键词： WE71 magnesium alloy Multi-direction forging Backward extrusion Bimodal grain structure Rare earths