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Compliant Control of Lower Limb Rehabilitation Exoskeleton Robot Based on Flexible Transmission

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Journal of Bionic Engineering 2023年第3期20卷 1021-1035页

作者： Keping Liu Li Li Wanting Li jian gu Zhongbo Sun Department of Control Science and Engineering Changchun University of TechnologyChangchun130012China Department of Electrical and Information Engineering Jilin Engineering Normal UniversityChangchun130052China

To ensure the safety, comfort, and effectiveness of lower limb rehabilitation exoskeleton robots in the rehabilitation training process, compliance is a prerequisite for human–machine interaction safety. First, under the premise of considering the mechanical structure of the lower limb rehabilitation exoskeleton robot (LLRER), when conducting the dynamic transmission of the exoskeleton knee joint, the soft axis is added to ensure that the rotation motion and torque are flexibly transmitted to any position to achieve flexible force transmission. Second, to realize the active compliance control of LLRER, the sliding mode impedance closed-loop controller is developed based on the kinematics and dynamics model of LLRER, and the stability of the designed control system is verified by Lyapunov method. Then the experiment is designed to track the collected bicycle rehabilitation motion data stably, and the algorithm and dynamic model are verified to satisfy the experimental requirements. Finally, aiming at the transmission efficiency and response performance of the soft shaft in the torque transmission process of the knee joint, the soft shaft transmission performance test is carried out to test the soft shaft transmission performance and realize the compliance of the LLRER, so as to ensure that the rehabilitation training can be carried out in a safe and comfortable interactive environment. Through the design of rehabilitation exercise training, it is verified that the LLRER of flexible transmission under sliding mode impedance control has good adaptability in the actual environment, and can achieve accurate and flexible control. During the experiment, the effectiveness of monitoring rehabilitation training is brought through the respiratory belt.

关键词： Lower limb rehabilitation exoskeleton Flexible control Impedance control Stability

Channel estimation in TDD mode

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The Journal of China Universities of Posts and Telecommunications 2006年第3期13卷 34-37页

作者： ZHANG Yi gu jian YANG Da-cheng School of Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

An efficient solution is proposed in this article for the channel estimation in time division duplex （TDD） mode wireless communication systems. In the proposed solution, the characteristics of fading channels in TDD mode systems are fully exploited to estimate the path delay of the fading channel. The corresponding amplitude is estimated using the minimum mean square error （MMSE） criterion. As a result, it is shown that the proposed novel solution is more accurate and efficient than the traditional solution, and the improvement is beneficial to the performance of Joint Detection.

关键词： channel estimation MMSE TDD

Anisotropic characteristics of granular materials under simple shear

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Journal of Central South University 2013年第8期20卷 2275-2284页

作者： QIAN jian-gu YOU Zi-pei HUANG Mao-song Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education (Tongji University) Shanghai 200092 China Department of Geotechnical Engineering Tongji University Shanghai 200092 China

The discrete element method was used to investigate the microscopic characteristics of granular materials under simple shear loading conditions. A series of simple tests on photo-elastic materials were used as a benchmark. With respect to the original experimental observations, average micro-variables such as the shear stress, shear strain and the volumetric dilatancy were extracted to illustrate the performance of the DEM simulation. The change of anisotropic density distributions of contact normals and contact forces was demonstrated during the course of simple shear. On the basis of microscopic characteristics, an analytical approach was further used to explore the macroscopic behaviors involving anisotropic shear strength and anisotropic stress-dilatancy. This results show that under simple shear loading, anisotropic shear strength arises primarily due to the difference between principal directions of the stress and the fabric. In addition, non-coaxiality, referring to the difference between principal directions of the strain rate and the stress, generates less stress-dilatancy. In particular, the anisotropic hardening and anisotropic stress-dilatancy will reduce to the isotropic hardening and the classical Taylor’s stress-dilatancy under proportional loading.

关键词： simple shear discrete element method anisotropy non-coaxiality

Pilot power based rate control in CDMA 2000 1x EV-DO Rev-A

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The Journal of China Universities of Posts and Telecommunications 2008年第1期15卷 118-122页

作者： LIU Xiao-feng gu jian YANG Hong-wen Wireless communication Center Beijing University of Posts andTelecommunications Beijing 100876 China

This article proposes a new algorithm to improve the rate control efficiency of enhanced reverse link medium access control （RLMAC） in the code division multiple access （CDMA） 1x EV-DO release A（Rev. A） system. The new algorithm brings reverse access terminal （AT） pilot power to the RLMAC rate control procedure and makes it easier for a low pilot power user to increase its data rate when the system is slightly loaded and harder to decrease its date rate when the system is heavily loaded. Numerical results of system level simulations show that the new algorithm can bring higher system throughput, lower AT transmission power, and lower system load.

关键词： RLMAC CDMA 1x EV-DO pilot power rate control

Micro-scale Cellular Automaton Modeling of Interface Evolution During Reaustenitization from Pearlite Structure in Steels

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Acta Metallurgica Sinica(English Letters) 2018年第7期31卷 713-722页

作者： Gang Shen Cheng-Wu Zheng jian-Feng gu Dian-Zhong Li Institute of Materials Modification and Modelling School of Materials Science and Engineering Shanghai Jiao Tong University Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Materials Genome Initiative Center Shanghai Jiao Tong University Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong University

A modified cellular automaton model is developed to depict the interface evolution inside the cementite plus ferrite lamellar microstructures during the reaustenitization of a pearlite steel. In this model, migrations of both the austenite- ferrite and austenite-cementite interfaces coupled with the carbon diffusion and redistribution are integrated. The capil- laxity effect derived from local interface curvatures is also carefully considered by involving the concentration given by the phase diagram modified by the Gibbs-Thomson effect. This allows the interface evolution from a transient state to a steady state under different annealing conditions and various interlamellar spacings to be simulated. The proposed cellular automaton approach could be readily used to describe the kinetics of austenite formation from the lamellar pearlites and virtually reveal the kinematics of the moving interfaces from the microstructural aspect.

关键词： Austenite formation Lamellar pearlite Interface evolution Cellular automaton Microstructural modeling

Syntheses and Crystal Structures of Methyl 2-(4,5-Dibromo-1-methylpyrrole-2-carbonylamino)-3-phenylpropanoate and 4,5-Dibromo-1-methyl-2- trichloroacetylpyrrole

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Chinese Journal of Structural Chemistry 2006年第2期25卷 153-158页

作者： ZENG Xiang-Chao gu jian XU Shi-Hai LIU Po-Run Department of Chemistry Jinan University Guangzhou 510632 China

4,5-Dibromo-1-methyl-2-trichloroacetylpyrrole Ⅰ, prepared by the reaction of 1-methyl-2-trichloroacetylpyrrole with Br2 in 98.6 % yield, was condensed with methyl L-2-amino-3- phenylpropanoate to afford methyl 2-（4,5-dibromo-1-methylpyrrole-2-carboxmido）-3-phenylpropanoate Ⅱ in 90.8% yield. Crystal data for Ⅰ： monoclinic system, space group P21/c with a = 8.595（3）, b = 10.900（4）, c = 12.321（5） ,A°,β = 92.292（7）°, V = 1153.4（8）A°^3, Dc = 2.213 g/cm^3, F（000） = 728, CTH4Br2Cl3NO, Mr = 384.28, λ = 0.71073 A°, μ（MoKa） = 7.688 mm^-1, Z = 4, R = 0.0338 and wR2 = 0.0840 for 1963 observed reflections with I 〉 2a（I）. Crystal data for Ⅱ： monoclinic system, space group P21 with a = 4.886（2）, b = 15.921（8）, c = 11.635（6） A°,β = 101.803（9）°, V = 885.9（7） A°^3, Dc = 1.665 g/cm^3, F（000） = 440, C16H16Br2N2O3, Mr = 444.13, λ = 0.71073 A°, μ（MoKa） = 4.590 mm^-1, Z = 2, R = 0.0335 and wR2 = 0.0837 for 3191 observed reflections with I 〉 2σ（I）. The crystal structure reveals that compound Ⅱ forms the one-dimensional chain structure via the intermolecular hydrogen bonds of N（2）-H…O（1）.

关键词： methyl 2-(4,5-dibromo-1-methylpyrrole-2-carbonylamino)-3-phenylpropanoate,synthesis crystal structure 4,5-dibromo-1-methyl-2-trichloroacetylpyrrole

Development and Evaluation of a Wearable Lower Limb Rehabilitation Robot

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Journal of Bionic Engineering 2022年第3期19卷 688-699页

作者： Wanting Li Keping Liu Chunxu Li Zhongbo Sun Shui Liu jian gu Department of Control Engineering Changchun University of TechnologyChangchun130012China Centre for Robotics and Neural Systems University of PlymouthPlymouthPL48AAUK School of Mechatronical Engineering Changchun University of TechnologyChangchun130012China

This paper introduces a rigid-flexible coupling wearable exoskeleton robot for lower limb,which is designed in light of gait biomechanics and beneficial for low limb movement disorders by implementing gait *** rationality of the proposed mechanism is shown with the implementation of the dynamic simulation through MSC *** the purposes of lightweight,the exoskeleton mechanism is optimized through finite element *** can be concluded from performance evaluation experiment,the mechanism has certain advantages over existing exoskeleton robots,namely,comfortable,lightweight,low cost,which can be utilized for rehabilitation training in medical institutions or as a daily-walking ancillary equipment for patients.

关键词： Wearable rehabilitation robot Biomechanics Robot mechanism design Virtual analysis

A Novel Method for Beckmann Rearrangement of Oximes with Silica Sulfuric Acid under Mild Condition

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Chinese Chemical Letters 2006年第5期17卷 617-620页

作者： Lin Fei XIAO Jia jian PENG Chun gu XIA State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences and Graduate School of Chinese Academy of Science Lanzhou 730000

Silica sulfuric acid in which sulfuric acid is immobilized on the surface of silica gel via covalent bond has been proved to be green catalyst for liquid-phase Beckmann rearrangement of oximes in dried dioxane at room temperature. Excellent conversion and selectivity were acquired in the Beckmann rearrangement of cyclohexanone oxime. The catalyst system was recycled and reused.

关键词： Beckmann rearrangement oximes silica sulfuric acid.

Synthesis and Crystal Structure of 3-(Pyrrole-2′-carboxamido)propanoic Acid·(1/2)H_(2)O

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Chinese Journal of Structural Chemistry 2005年第7期24卷 779-782,737页

作者： ZENG Xiang-Chao XU Shi-Hai gu jian LIU Po-Run Department of Chemistry Jinan UniversityGuangzhou 510632China

3-(Pyrrole-2?-carboxamido)propanoic acid I has been synthesized from the reaction of β-alanine methyl ester with 2-trichloroacetylpyrrole followed by saponifying and acidating in 85.4% yield, and the crystal structure of 3-(pyrrole-2?-carboxamido)propanoic acid· (1/2)H2O (C8H11N2O3.5, Mr = 191.19) was obtained and determined by X-ray diffraction method. The crystal is of monoclinic, space group C2/c with a = 19.010(4), b = 8.3515(17), c = 13.788(3) ?, β = 125.88(3)o, V = 1773.6(6) ?3, Z = 8, Dc = 1.432 g/cm3, λ = 0.71073 ?, μ(MoKα) = 0.114 mm?1 and F(000) = 768. The structure was refined to R = 0.0354 and wR = 0.0942 for 1642 observed reflections with I > 2σ(I). It is revealed that the title compound has one pyrrole ring and one propionic acid subchain linked by an amido bond at C(4), and there are 8 molecules of com- pound I and 4 crystal water molecules in each unit cell. The supramolecular layers are stabilized by the hydrogen bonds of N(2) H…O(2), N(1) H…O(4), O(4) H(1W)…O(2) and O(3) H…O(1).

关键词： 3-(pyrrole-2′-carboxamido)propanoic acid 2-trichloroacetylpyrrole crystal structure