Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling ca...Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological features.Firstly,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain synthesis.Secondly,the screw theory is employed to analyze the degree of freedom(DoF)of the capture mechanism.Then,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried out.Combined with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried out.Furthermore,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are analyzed.Finally,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is completed.The work provides technical reserves for the research and development of AUV capture special equipment.展开更多
A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of whee...A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.展开更多
Deployable mechanism with preferable deployable performance,strong expansibility,and lightweight has attracted much attention because of their potential in aerospace.A basic deployable pyramid unit with good deployabi...Deployable mechanism with preferable deployable performance,strong expansibility,and lightweight has attracted much attention because of their potential in aerospace.A basic deployable pyramid unit with good deployability and expandability is proposed to construct a sizeable deployable mechanism.Firstly,the basic unit folding principle and expansion method is proposed.The configuration synthesis method of adding constraint chains of spatial closed-loop mechanism is used to synthesize the basic unit.Then,the degree of freedom of the basic unit is analyzed using the screw theory and the link dismantling method.Next,the three-dimensional models of the pyramid unit,expansion unit,and array unit are established,and the folding motion simulation analysis is carried out.Based on the number of components,weight reduction rate,and deployable rate,the performance characteristics of the three types of mechanisms are described in detail.Finally,prototypes of the pyramid unit,combination unit,and expansion unit are developed to verify further the correctness of the configuration synthesis based on the pyramid.The proposed deployable mechanism provides aference for the design and application of antennas with a large aperture,high deployable rate,and lightweight.It has a good application prospect in the aerospace field.展开更多
Origami mechanisms are extensively employed in various engineering applications due to their exceptional folding performance and deformability.The key to designing origami mechanisms lies in the design of the creases....Origami mechanisms are extensively employed in various engineering applications due to their exceptional folding performance and deformability.The key to designing origami mechanisms lies in the design of the creases.The crease design is often derived from experience and inspiration,so it is crucial to have a systematic approach to crease design.In this paper,a novel synthesis approach based on graph theory is proposed,which effectively addresses the challenge of designing the creases in origami mechanisms.The essence of this method lies in the acquisition of the double symmetrical crease pattern through the directed graph product operation of two subgraphs.The crease pattern can be simplified by employing a technique that eliminates certain creases while preserving the non-isomorphism and symmetry of the pattern.An improved mixed-integer linear programming model is developed to achieve an automatic distribution of the peak_valley creases of the origami.The proposed method ultimately generates 12 unique double symmetrical crease patterns.The new method proposed in this paper,through systematic design,significantly improves the efficiency of mechanism design while opening up broad prospects for exploring new mechanism structures,thereby greatly expanding its application potential in cutting-edge fields such as aerospace engineering and intelligent robots.展开更多
Four exotic chiral organocatalysts, 9-amino-（9-deoxy） cinchona alkaloids with （8S, 9R） and （8R, 9S）- configurations, were conveniently synthesized for the first time in 27-72% total yields through two conversion...Four exotic chiral organocatalysts, 9-amino-（9-deoxy） cinchona alkaloids with （8S, 9R） and （8R, 9S）- configurations, were conveniently synthesized for the first time in 27-72% total yields through two conversions of configuration at the 9-stereogenic centers of commercially available cinchona alkaloids.展开更多
Aircraft have received much attention because of their capability to adapt to various flight environments and complex missions.The nose cone is one of the key elements in optimising the aerodynamic shape of aircraft.A...Aircraft have received much attention because of their capability to adapt to various flight environments and complex missions.The nose cone is one of the key elements in optimising the aerodynamic shape of aircraft.A morphing nose cone(MNC)driven by a biomimetic 4-3R1U&3R sparallel mechanism is proposed in this study.Based on screw theory,the parallel mechanism’s configuration is determined,and the structure’s full-cycle degrees of freedom are concurrently confirmed.Examples in the paper demonstrate the viability of the structure by configuration synthesis,and diagrams also show the chains.This MNC is modelled after the structural design of the cicada’s abdomen and can be extended,contracted and bent.It can actively adjust its shape in response to change in the flight environments,thereby aerodynamic performance and enhancing the aircraft’s multi-mission capabilities.A scaled-down prototype is created to verify the deformation capacity of the MNC meeting the engineering requirements.Results show that the extension ratio is 36.7%,and the bending angle is 21.7°,which is better than expected.The relative error value is within a reasonable range and the extension process is incredibly stable.This research proposes new perspectives for the design of MNCs.展开更多
Till now, it is generally reported that Cu（bipy）<sub>3</sub>Cl<sub>2</sub> coordinative compound has an octahedra configuration with six coordination numbers and can be prepared. In the 1960s...Till now, it is generally reported that Cu（bipy）<sub>3</sub>Cl<sub>2</sub> coordinative compound has an octahedra configuration with six coordination numbers and can be prepared. In the 1960s, some queries arose but failed to change the common viewpoint for lack of full evidence.展开更多
Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methan...Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methanol production unit, which are approximately15.018 t·h^(-1) in the largest methanol production complexes in the world, can be recycled to the reactor and utilized for increasing the production rate. Purge gas streams contain 63% hydrogen,20% carbon monoxide and carbon dioxide as reactants and 17% nitrogen and methane as inert. The recycling effect of beneficial components on methanol production rate has been investigated in this study. Simulation results show that methanol production enhances by recycling just hydrogen, carbon dioxide and carbon monoxide which is an effective configuration among the others. It is named as Desired Recycle Configuration(DRC) in this study. The optimum fraction of returning purge gas is calculated via one dimensional modeling of process and Response Surface Methodology(RSM) is applied to maximize the methanol flow rate and minimize the carbon dioxide flow rate. Simulation results illustrate that methanol flow rate increases by 0.106% in DRC compared to Conventional Recycle Configuration(CRC) which therefore shows the superiority of applying DRC to CRC.展开更多
Today＇s manufacturing cnvironmem forces manufacturing companies to make as many product variations as possible at affordable costs within a short time. Mass customisation is one of most important technologies for com...Today＇s manufacturing cnvironmem forces manufacturing companies to make as many product variations as possible at affordable costs within a short time. Mass customisation is one of most important technologies for companies to achieve their objectives. Efforts to mass customisation should be made on two aspects： （1） To modularize products and make them as less differences as possible; （2） To design manufacturing resources and make them provide as many processes variations as possible. This paper reports our recent work on aspect （2）, i.e. how to design a reconfignrable manufacturing system （RMS） so that it can be competent to accomplish various processes optimally; Reconfignrable robot system （RRS） is taken as an example. RMS design involves architecture design and configuration design, and configuration design is further divided in design analysis and design synthesis. Axiomatic design theory （ADT） is applied to architecture design, the features and issues of RRS configuration design are discussed, automatic modelling method is developed for design analysis, and concurrent design methodology is presented for design synthesis.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20220649)the Natural Science Foundation of the Jiangsu Higher Education Institutions(Grant No.23KJB460010)+1 种基金the Key R&D Program of Jiangsu Province(Grant No.BE2022062)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.SJCX23_2143).
文摘Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological features.Firstly,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain synthesis.Secondly,the screw theory is employed to analyze the degree of freedom(DoF)of the capture mechanism.Then,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried out.Combined with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried out.Furthermore,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are analyzed.Finally,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is completed.The work provides technical reserves for the research and development of AUV capture special equipment.
基金Supported by National "863" High-Tech Program (No.2006AA04Z231)Foundation of State Key Laboratory of Robotics and Systems (No.SKLRS-200801A02)+1 种基金the College Discipline Innovation Wisdom Plan (No.B07018)Natural Science Foundation of Heilongjiang Province (No.ZJG0709)
文摘A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.
基金Supported by National Natural Science Foundation of China(Grant No.52075467)Jiangsu Provincial Natural Science Foundation of China(Grant No.BK20220649)+1 种基金Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.23KJB460010)Jiangsu Provincial Key R&D Project(Grant No.BE2022062).
文摘Deployable mechanism with preferable deployable performance,strong expansibility,and lightweight has attracted much attention because of their potential in aerospace.A basic deployable pyramid unit with good deployability and expandability is proposed to construct a sizeable deployable mechanism.Firstly,the basic unit folding principle and expansion method is proposed.The configuration synthesis method of adding constraint chains of spatial closed-loop mechanism is used to synthesize the basic unit.Then,the degree of freedom of the basic unit is analyzed using the screw theory and the link dismantling method.Next,the three-dimensional models of the pyramid unit,expansion unit,and array unit are established,and the folding motion simulation analysis is carried out.Based on the number of components,weight reduction rate,and deployable rate,the performance characteristics of the three types of mechanisms are described in detail.Finally,prototypes of the pyramid unit,combination unit,and expansion unit are developed to verify further the correctness of the configuration synthesis based on the pyramid.The proposed deployable mechanism provides aference for the design and application of antennas with a large aperture,high deployable rate,and lightweight.It has a good application prospect in the aerospace field.
基金Supported by National Natural Science Foundation of China(Grant Nos.52375028,52205040)Hebei Provincial Natural Science Foundation(Grant Nos.E2024203052,E2024203105)Science and Technology Project of Hebei Education Department(Grant No.QN2023206).
文摘Origami mechanisms are extensively employed in various engineering applications due to their exceptional folding performance and deformability.The key to designing origami mechanisms lies in the design of the creases.The crease design is often derived from experience and inspiration,so it is crucial to have a systematic approach to crease design.In this paper,a novel synthesis approach based on graph theory is proposed,which effectively addresses the challenge of designing the creases in origami mechanisms.The essence of this method lies in the acquisition of the double symmetrical crease pattern through the directed graph product operation of two subgraphs.The crease pattern can be simplified by employing a technique that eliminates certain creases while preserving the non-isomorphism and symmetry of the pattern.An improved mixed-integer linear programming model is developed to achieve an automatic distribution of the peak_valley creases of the origami.The proposed method ultimately generates 12 unique double symmetrical crease patterns.The new method proposed in this paper,through systematic design,significantly improves the efficiency of mechanism design while opening up broad prospects for exploring new mechanism structures,thereby greatly expanding its application potential in cutting-edge fields such as aerospace engineering and intelligent robots.
基金Research support from the National Science Foundation ofChina(No.21071116)Chongqing Scientific Foundation,China(No.2010BB4126)
文摘Four exotic chiral organocatalysts, 9-amino-（9-deoxy） cinchona alkaloids with （8S, 9R） and （8R, 9S）- configurations, were conveniently synthesized for the first time in 27-72% total yields through two conversions of configuration at the 9-stereogenic centers of commercially available cinchona alkaloids.
基金Supported by Hebei Provincial Natural Science Foundation(Grant Nos.E2024203052,E2024203105)National Natural Science Foundation of China(Grant No.52375028)Science and Technology Project of Hebei Education Department(Grant No.QN2023206).
文摘Aircraft have received much attention because of their capability to adapt to various flight environments and complex missions.The nose cone is one of the key elements in optimising the aerodynamic shape of aircraft.A morphing nose cone(MNC)driven by a biomimetic 4-3R1U&3R sparallel mechanism is proposed in this study.Based on screw theory,the parallel mechanism’s configuration is determined,and the structure’s full-cycle degrees of freedom are concurrently confirmed.Examples in the paper demonstrate the viability of the structure by configuration synthesis,and diagrams also show the chains.This MNC is modelled after the structural design of the cicada’s abdomen and can be extended,contracted and bent.It can actively adjust its shape in response to change in the flight environments,thereby aerodynamic performance and enhancing the aircraft’s multi-mission capabilities.A scaled-down prototype is created to verify the deformation capacity of the MNC meeting the engineering requirements.Results show that the extension ratio is 36.7%,and the bending angle is 21.7°,which is better than expected.The relative error value is within a reasonable range and the extension process is incredibly stable.This research proposes new perspectives for the design of MNCs.
基金Project supported by the National Natural Science Foundation of China
文摘Till now, it is generally reported that Cu（bipy）<sub>3</sub>Cl<sub>2</sub> coordinative compound has an octahedra configuration with six coordination numbers and can be prepared. In the 1960s, some queries arose but failed to change the common viewpoint for lack of full evidence.
文摘Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methanol production unit, which are approximately15.018 t·h^(-1) in the largest methanol production complexes in the world, can be recycled to the reactor and utilized for increasing the production rate. Purge gas streams contain 63% hydrogen,20% carbon monoxide and carbon dioxide as reactants and 17% nitrogen and methane as inert. The recycling effect of beneficial components on methanol production rate has been investigated in this study. Simulation results show that methanol production enhances by recycling just hydrogen, carbon dioxide and carbon monoxide which is an effective configuration among the others. It is named as Desired Recycle Configuration(DRC) in this study. The optimum fraction of returning purge gas is calculated via one dimensional modeling of process and Response Surface Methodology(RSM) is applied to maximize the methanol flow rate and minimize the carbon dioxide flow rate. Simulation results illustrate that methanol flow rate increases by 0.106% in DRC compared to Conventional Recycle Configuration(CRC) which therefore shows the superiority of applying DRC to CRC.
文摘Today＇s manufacturing cnvironmem forces manufacturing companies to make as many product variations as possible at affordable costs within a short time. Mass customisation is one of most important technologies for companies to achieve their objectives. Efforts to mass customisation should be made on two aspects： （1） To modularize products and make them as less differences as possible; （2） To design manufacturing resources and make them provide as many processes variations as possible. This paper reports our recent work on aspect （2）, i.e. how to design a reconfignrable manufacturing system （RMS） so that it can be competent to accomplish various processes optimally; Reconfignrable robot system （RRS） is taken as an example. RMS design involves architecture design and configuration design, and configuration design is further divided in design analysis and design synthesis. Axiomatic design theory （ADT） is applied to architecture design, the features and issues of RRS configuration design are discussed, automatic modelling method is developed for design analysis, and concurrent design methodology is presented for design synthesis.
