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Design of an Active Flexible Spine for Wall Climbing Robot Using Pneumatic Soft Actuators

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Journal of Bionic Engineering 2023年第2期20卷 530-542页

作者： Guangming Chen Tao Lin Gabriel Lodewijks Aihong Ji Lab of Locomotion Bioinspiration and Intelligent Robots College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and Astronautics29 Yudao StreetNanjing210016China School of Engineering College of EngineeringScience&EnvironmentUniversity of NewcastleCallaghan CampusUniversity DriveCallaghanNSW2308Australia

Wall climbing robots can be used to undertake missions in many unstructured environments.However,current wall climbing robots have mobility difficulties such as in the turning or accelarating.One of the main reasons for the limitations is the poor flexibility of the spines.Soft robotic technology can actively enable structure deformation and stiffness varations,which provides a solution for the design of active flexible spines.This research utilizes pneumatic soft actuators to design a flexible spine with the abilities of actively bending and twisting by each joint.Using bending and torsion moment equilibriums,respectively,from air pressure to material deformations,the bending and twisting models for a single actuator with respect to different pressure are obtained.The theoretical models are verified by finite-element method simulations and experimental tests.In addition,the bending and twisiting motions of single joint and whole spine are analytically modeled.The results show that the bionic spine can perform desired deformations in accordance with the applied pressure on specified chambers.The variations of the stiffness are also numerically assessed.Finally,the effectiveness of the bionic flexible spine for actively producing sequenced motions as biological spine is experimentally validated.This work demonstrated that the peneumatic spine is potential to improve the spine flexibility of wall climbing robot.

关键词： Active spine Bionic design Soft robot Gecko locomotion Finite-element modeling

Construction of a cement-rebar nanoarchitecture for a solution-processed and flexible film of a Bi_(2)Te_(3)/CNT hybrid toward low thermal conductivity and high thermoelectric performance

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Carbon Energy 2022年第1期4卷 115-128页

作者： Zhijun chen Haicai Lv Qichun Zhang Hanfu Wang Guangming Chen College of Materials Science and Engineering Shenzhen UniversityShenzhenChina College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhenChina Department of Materials Science and Engineering City University of Hong KongHong KongChina Center of Super-Diamond and Advanced Films(COSDAF) City University of Hong KongHong KongChina National Center for Nanoscience and Technology BeijingChina

Solution processability and flexibility still remain major challenges for many thermoelectric(TE)materials,including bismuth telluride(Bi_(2)Te_(3)),a typical and commercially available TE material.Here,we report a new solutionprocessed method to prepare a flexible film of a Bi_(2)Te_(3)/single-walled carbon nanotube(SWCNT)hybrid,where the dissolved Bi_(2)Te_(3) ion precursors are mixed with dispersed SWCNTs in solution and recrystallized on the SWCNT surfaces to form a“cement-rebar”-like architecture.The hybrid film shows an n-type characteristic,with a stable Seebeck coefficient of^(−1)00.00±1.69μVK^(−1) in air.Furthermore,an extremely low in-plane thermal conductivity of∼0.33Wm^(−1) K^(−1) is achieved at 300 K,and the figure of merit(ZT)reaches 0.47±0.02.In addition,the TE performance is independent of mechanical bending.The unique“cement-rebar”-like architecture is believed to be responsible for the excellent TE performances and the high flexibility.The results provide a new avenue for the fabrication of solution-processable and flexible TE hybrid films and will speed up the applications of flexible electronics and energy conversion.

关键词： Bi_(2)Te_(3) carbon nanotube hybrid solution-processed thermoelectrics

Effect of Dual-Tasks Walking on Human Gait Patterns

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Journal of Bionic Engineering 2022年第4期19卷 991-1002页

作者： Xiyuan Zhang Ke Rong Guangming Chen Aihong Ji Yawei Song Lab of Locomotion Bioinspiration and Intelligent Robots College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and Astronautics29 Yudao StreetNanjing 210016China Olympic College Communication University of China NanjingNanjing 211162China Department of Sports Health Sciences Nanjing Sport Institute8 Linggusi RoadNanjing 210014China Centre of Scientific Experiment Nanjing Sport InstituteNanjing 210014China

A human gait pattern conformed to the law of the inverted pendulum and could be described by the movement of its center of mass(COM).A sinusoidal function based on an inverted pendulum was used to plan the COM trajectory of humanoid robots for gait control.Therefore,studying the human dual-tasks gait pattern is essential for improving the gait adaptability of humanoid robots.Many well-known humanoid robot prototypes can complete stable walking,running,jumping,and other movements closely mimicking human beings.This study provides a theoretical reference for the gait planning and design of humanoid robots by comparing differences in the stride time,cadence,step length,step width,stride length,walking speed and COM movement during single-and dual-tasks walking.Results showed no significant difference in the time parameters.In dual-tasks walking,the walking speeds decreased(P=0.001)and the COM sidewise movement increased,indicating an enhancement in the automatic motion rhythm in cognitive tasks.Humans can easily select new different speeds to better adapt to the competition of attention resources.To enhance the adaptability of humanoid robots to the COM offset,the independent motion of the hip joint separated from the trunk and lower limbs must be considered in the robot design.

关键词： Gait analysis Kinematics COM trajectory Kinesiology

Regulating Thermogalvanic Effect and Mechanical Robustness via Redox Ions for Flexible Quasi‑Solid‑State Thermocells

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Nano-Micro Letters 2022年第5期14卷 153-167页

作者： Peng Peng Jiaqian Zhou Lirong Liang Xuan Huang Haicai Lv Zhuoxin Liu Guangming Chen College of Materials Science and Engineering Shenzhen UniversityShenzhen 518055People’s Republic of China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060People’s Republic of China

The design of power supply systems for wearable applications requires both flexibility and durability.Thermoelectrochemical cells(TECs)with large Seebeck coefficient can efficiently convert lowgrade heat into electricity,thus having attracted considerable attention in recent years.Utilizing hydrogel electrolyte essentially addresses the electrolyte leakage and complicated packaging issues existing in conventional liquid-based TECs,which well satisfies the need for flexibility.Whereas,the concern of mechanical robustness to ensure stable energy output remains yet to be addressed.Herein,a flexible quasisolid-state TEC is proposed based on the rational design of a hydrogel electrolyte,of which the thermogalvanic effect and mechanical robustness are simultaneously regulated via the multivalent ions of a redox couple.The introduced redox ions not only endow the hydrogel with excellent heat-to-electricity conversion capability,but also act as ionic crosslinks to afford a dual-crosslinked structure,resulting in reversible bonds for effective energy dissipation.The optimized TEC exhibits a high Seebeck coefficient of 1.43 mV K−1 and a significantly improved fracture toughness of 3555 J m^(−2),thereby can maintain a stable thermoelectrochemical performance against various harsh mechanical stimuli.This study reveals the high potential of the quasi-solid-state TEC as a flexible and durable energy supply system for wearable applications.

关键词： Thermocells Thermoelectric Flexible energy devices Wearable applications Hydrogel electrolytes

Carbon and carbon composites for thermoelectric applications

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Carbon Energy 2020年第3期2卷 408-436页

作者： Yichuan Zhang Qichun Zhang Guangming Chen College of Materials Science and Engineering Shenzhen UniversityShenzhenP.R.China School of Materials Science and Engineering Nanyang Technological UniversitySingapore Department of Materials Science and Engineering City University of Hong KongKowloonHong Kong SARChina

The urgent need for consistent,reliable,ecofriendly,and stable power sources drives the development of new green energy materials.Thermoelectric(TE)materials receive increasing attention due to their unique capability of realizing the direct energy conversion between heat and electricity,showing diverse applications in harvesting waste heat and low-grade heat.Carbon materials such as carbon nanotubes(CNTs)and graphene have experienced a rapid development as TE materials because of their intrinsic ultrahigh electrical conductivity and light weight.Besides,polymer-based carbon composites are particularly fascinating as the combination of the merits of polymers and filler materials leads to high TE performance and superior flexibility.Herein,the recent TE advances are systematically summarized in the studied popularity of carbon materials(ie,CNTs and graphene)and the category of polymers.The conducting polymer-based carbon materials are particularly highlighted.Finally,the remaining challenges and some tentative suggestions possibly guiding future developments are proposed,which may pave a way for a bright future of carbon and carbon composites in the energy market.

关键词： carbon nanotubes conducting polymers graphene thermoelectric materials thermoplastic polymers

Synthesis of 2-Trifluoromethyl-4-aminoquinolines via Heating-Promoted Multi-component Reaction of CF_(3)-Imidoyl Sulfoxonium Ylides and Amines with Difluorocarbene as a C1 Synthon

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Chinese Journal of Chemistry 2023年第23期41卷 3205-3210页

作者： guangming Wei chen Li Haoyuan Wang Zhengkai chen Xiao-Feng Wu School of Chemistry and Chemical Engineering Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang ProvinceZhejiang Sci-Tech UniversityHangzhouZhejiang310018 China Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning116023 China Leibniz-Institut für Katalyse e.V. Albert-Einstein-Straβe 29a18059RostockGermany

A thermally-induced multi-component reaction of CF_(3)-substituted imidoyl sulfoxonium ylides(TFISYs),amines and(triphenylphosphonio)difluoroacetate(PDFA)has been developed,allowing a facile access to 2-trifluoromethyl-4-aminoquinolines in high yields.The reaction proceeds smoothly with or without the addition of sulfur and utilizes difluorocarbene as a C1 synthon under simply heating conditions.Mechanistic study reveals that in-situ generated thiocarbonyl fluoride,isothiocyanate or gem-difluoroalkene might act as the key reaction intermediates.

关键词： CF_(3)-Imidoyl sulfoxonium ylides Difluorocarbene Multi-component reaction 2-Trifluoromethyl-4-aminoquinolines N-Heterocyclic compounds

Unified Analysis and Output Estimation for a Strong Coupling Contactless Slipring System

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CSEE Journal of Power and Energy Systems 2023年第6期9卷 2263-2271页

作者： guangming He Qianhong chen Xiaoyong Ren Zhiliang Zhang the Jiangsu Key Laboratory of New Energy Generation and Power Conversion Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Physics and Electronic Electrical Engineering Huaiyin Normal UniversityHuai’an 223300China

A contactless slipring (CS) system utilizing inductive-power-transfer (IPT) technology is a good candidate for traditional mechanical slipring assemblies. However, suffering from the high harmonic currents in strong coupling CS systems, the output power will deviate from the theoretical values estimated by the fundamental harmonic approximation (FHA) and its extension method, i.e., E-FHA, in which the power is transferred by both the fundamental current and the high order harmonic currents. In order to achieve high precise output estimation, a unified analysis is proposed in this paper. First, “Fundamental-harmonic Double Resonance Phenomenon” is revealed via impedance analysis, to address the nature of the high harmonic currents in strong coupling systems. Then, a unified output current expression owning high precision is derived, and followed by a unified fundamental load impedance. Discussions show that both the output and the fundamental load impedance of FHA, and E-FHA are the special cases of the unified expressions proposed. FHA and E-FHA are precise enough for the loose coupling system, whereas the proposed method is indispensable for the strong coupling system with k>0.4 . Finally, simulations and experimental measurements of a 1.6kW CS system, as well as the comparative studies related to FHA, E-FHA, and the proposed method, are presented, indicating that the proposed method is effective for high precise output estimation.

关键词： Contactless slipring(CS) precise output estimation unified analysis

Flexible nanocomposite electrodes with optimized hybrid structure for improved low-grade heat harvest via thermocells

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Science China Chemistry 2023年第6期66卷 1814-1823页

作者： Ziwei Mo Jiaqian Zhou Xin Lu Lirong Liang Fusheng Liu Zhuoxin Liu Guangming Chen College of Materials Science and Engineering Shenzhen UniversityShenzhen 518055China State Key Laboratory of Polymer Materials Engineering Sichuan UniversityChengdu 610065China

Thermal energy is ubiquitous and constantly generated in nature and society.Thermocells(TECs)represent a promising energyconversion technology that can directly translate thermal energy into electricity with a large thermopower,thus having attracted considerable attention in recent years.Nevertheless,the use of noble platinum electrodes in TECs has substantially limited their widespread applications,as the scarcity of platinum element increases the cost of materials,and its intrinsic rigidity is not conducive to flexible and wearable applications under heat sources with complex surface geometry.Herein,we propose a facile hybridizing route to constructing flexible electrodes with optimized nanostructures.The flexible composite electrode is fabricated by decorating a single-walled carbon nanotube network with conducting polypyrrole nanospheres through controlled electrochemical deposition.With refined interfacial nanostructures,the resultant composite film can facilitate carrier transport/transfer at the electrolyte-electrode interface,and thereby shows superior overall thermoelectrochemical performance to noble platinum electrode.The TEC employing the flexible composite electrodes yields a maximum output power of 2.555μW under the temperature difference of 30 K,and a device comprising 6 TEC units is assembled to efficiently utilize waste heat and human body heat,revealing the high potential of low-grade heat harvesting.

关键词： nanocomposites thermocells carbon nanotubes polymers

Numerical Evaluation of Residual Water Content after Freezing during the Lyophilization of Platelets

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Fluid Dynamics & Materials Processing 2020年第6期16卷 112-124页

作者： Shaozhi Zhang Ruoyi Xie Mengjie Xu Guangming Chen Key Laboratory of Refrigeration and Cryogenic Technology of Zhejiang Province Institute of Refrigeration and CryogenicsZhejiang UniversityHangzhou310027China

Pre-freezing is an important stage in freeze-drying processes.For the lyophilization of a cell,freezing not only plays a role for primary dehydration,but it also determines the amount of residual(intracellular or extracellular)water,which in turn can influence the solution properties and the choice of operation parameters.The freezing of human platelets in lyoprotectant solution is theoretically investigated here.A two-parameter model and an Arrhenius expression are used to describe cell membrane permeability and its temperature dependency.It is assumed that the intracellular solution is composed of four components:sodium chloride,trehalose,serum protein and water,while the extracellular solution consists of three components.Non-ideal solution behaviors are predicted using measured data.The concentration of maximally freeze-concentrated solution is estimated on the basis of an assumption of solute hydration.The impacts of lyoprotectant composition and extracellular sub-cooling on intracellular supercooling and residual water content in the cell are analyzed.The values of activation energy of hydraulic permeability at low temperatures are tested to study their impact on the critical cooling rate.As the mass fraction extracellular lyoprotectant(trehalose+bovineserum albumin)increases from 5 wt%to 20 wt%,the intracellular water content at the end of freezing does not change,but the intracellular solution undergoes much higher super-cooling degree.Increasing the mass ratio of trehalose to bovine serum albumin does not change the intracellular water content,but can mitigate intracellular super-cooling.While 0.05 mol/kg trehalose is loaded into platelet,the total quantity of residual water at the end of freezing may raise by 4.93%.The inclusion of dimethyl sulfoxide(Me2SO)in protectant may bring negative impacts to the drying stage by increasing the residual water content and lowering the drying temperature.

关键词： Lyophilization human platelets freezing numerical simulation