In product concept design, not only designers with professional CAD skills, but also final customers take part in the design and evaluation of product shape styling. Because customers usually lack surface modelling ba...In product concept design, not only designers with professional CAD skills, but also final customers take part in the design and evaluation of product shape styling. Because customers usually lack surface modelling background and are not familiar with concrete operations of commercial CAD systems, it is difficult for them to express their change intentions of product shape through professional CAD tools if they are not satisfied with the current shape design. This paper puts forward a method for creating, dragging and manipulating constraint and load represented in form of icon entity in interactive sculpting of product shape in virtual environment. The method supports customers manipulation of sculpting constraints or loads on sculpting shapes in virtual reality interaction to control the deformation of product shape. Constraints management based on icon entity is similar to spline lofting operation that is familiar to engineers, so users do not need to know surface details or have any professional knowledge of surface modelling, by only using their physical and engineering experience, they can manipulate the sculpting of product shape intuitively.展开更多
Droplet manipulation on an open surface has great potential in chemical analysis and biomedicine engineering.However,most of the reported platforms designed for the manipulation of water droplets cannot thoroughly sol...Droplet manipulation on an open surface has great potential in chemical analysis and biomedicine engineering.However,most of the reported platforms designed for the manipulation of water droplets cannot thoroughly solve the problem of droplet evaporation.Herein,we report a shape-reconfigurable micropillar array chip for the manipulation of water droplets,oil droplets and water-in-oil droplets.Water-in-oil droplets provide an enclosed space for water droplets,preventing the evaporation in an open environment.Perfluoropolyether coated on the surface of the chip effectively reduces the droplet movement resistance.The micropillar array chip has light and magnetic dual-response due to the Fe3O4 nanoparticles and the reduced iron powder mixed in the shape-memory polymer.The micropillars irradiated by a near-infrared laser bend under the magnetic force,while the unirradiated micropillars still keep their original shape.In the absence of a magnetic field,when the micropillars in a temporary shape are irradiated by the near-infrared laser to the transition temperature,the micropillars return to their initial shape.In this process,the surface morphology gradient caused by the deformation of the micropillars and the surface tension gradient caused by the temperature change jointly produce the driving force of droplet movement.展开更多
This paper reviews recent developments in nonlinear control technologies for shape memory alloy (SMA) actuators in robotics and their related applications. SMA possesses large hysteresis, low bandwidth, slow response,...This paper reviews recent developments in nonlinear control technologies for shape memory alloy (SMA) actuators in robotics and their related applications. SMA possesses large hysteresis, low bandwidth, slow response, and non-linear behavior, which make them difficult to control. The fast response of the SMA actuator mostly depends upon, (1) type of controller, (2) rate of addition and removal of heat, and (3) shape or form of the actuator. Though linear controllers are more desirable than nonlinear ones, the review of literature shows that the results obtained using nonlinear controllers were far better than the former one. Therefore, more emphasis is made on the nonlinear control technologies taking into account the intelligent controllers. Various forms of SMA actuator along with different heating and cooling methods are presented in this review, followed by the nonlinear control methods and the control problems encountered by the researchers.展开更多
Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus ...Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus light through inhomogeneous media, which is vital for optical imaging, communication,therapy, etc. Wavefront shaping based on the scattering matrix (SM) is extremely useful in handling dynamicprocesses in the linear regime. However, the implementation of such a method for controlling light in nonlinearmedia is still a challenge and has been unexplored until now. We report a method to determine the SM ofnonlinear scattering media with second-order nonlinearity. We experimentally demonstrate its feasibility inwavefront control and realize focusing of nonlinear signals through strongly scattering quadratic media.Moreover, we show that statistical properties of this SM still follow the random matrix theory. The scattering-matrix approach of nonlinear scattering medium opens a path toward nonlinear signal recovery, nonlinearimaging, microscopic object tracking, and complex environment quantum information processing.展开更多
Shape skeletonization （i.e., medial axis extraction） is powerful in many visual computing applications, such as pattern recognition, object segmentation, registration, and animation. In this paper, the authors expan...Shape skeletonization （i.e., medial axis extraction） is powerful in many visual computing applications, such as pattern recognition, object segmentation, registration, and animation. In this paper, the authors expand the use of diffusion equations combined with distance field information to approximate medial axes of arbitrary 3D differential properties. It offers an alternative solids represented by polygonal meshes based on their but natural way for medial axis extraction for commonly used 3D polygonal models. By solving the PDE along time axis, this system can not only quickly extract diffusion-based medial axes of input meshes, but also allow users to visualize the extraction process at each time step. In addition, the proposed model provides users a set of manipulation toolkits to sculpt extracted medial axes, then use diffusion-based techniques to recover corresponding deformed shapes according to the original input datasets. This skeleton-based shape manipulation offers a fast and easy way for animation and deformation of complicated mesh objects.展开更多
目的针对摇盖式异形烟盒烟支入盒工艺普遍使用手工包装,导致生产效率低下且易产生二次污染等问题,提出使用真空吸附式机械手完成烟支入盒流程,并对机械手末端真空吸盒的结构进行优化设计。方法应用FLUENT软件对3种不同结构型式真空吸盒...目的针对摇盖式异形烟盒烟支入盒工艺普遍使用手工包装,导致生产效率低下且易产生二次污染等问题,提出使用真空吸附式机械手完成烟支入盒流程,并对机械手末端真空吸盒的结构进行优化设计。方法应用FLUENT软件对3种不同结构型式真空吸盒的二维流场进行数值模拟分析,得到吸盒端口结构型式及真空度与负压气流场稳定性的影响关系。结果负压气流场稳定性强弱关系为锥形>圆形>方形;随着真空度的增加,吸盒端口中心及吸孔入口流速均增加,负压气流场内真空度越大,其稳定性越差,当真空度分别为20,25,30,40 k Pa时,锥形吸盒气流场的理想真空度为20 k Pa。结论设计的烟支入盒工艺合理,稳定性好,效率高。模拟结果可给真空吸盒的优化设计提供理论依据。展开更多
基金Project supported by the National Basic Research (973) Program (Nos. 2004CB719402 and 2002CB312106) of China, and the National Natural Science Foundation (Nos. 50305033 and 60375020) of China
文摘In product concept design, not only designers with professional CAD skills, but also final customers take part in the design and evaluation of product shape styling. Because customers usually lack surface modelling background and are not familiar with concrete operations of commercial CAD systems, it is difficult for them to express their change intentions of product shape through professional CAD tools if they are not satisfied with the current shape design. This paper puts forward a method for creating, dragging and manipulating constraint and load represented in form of icon entity in interactive sculpting of product shape in virtual environment. The method supports customers manipulation of sculpting constraints or loads on sculpting shapes in virtual reality interaction to control the deformation of product shape. Constraints management based on icon entity is similar to spline lofting operation that is familiar to engineers, so users do not need to know surface details or have any professional knowledge of surface modelling, by only using their physical and engineering experience, they can manipulate the sculpting of product shape intuitively.
基金the Natural Science Foundation of China(No.21874015)the Fundamental Research Funds for the Central Universities(No.N2005024).
文摘Droplet manipulation on an open surface has great potential in chemical analysis and biomedicine engineering.However,most of the reported platforms designed for the manipulation of water droplets cannot thoroughly solve the problem of droplet evaporation.Herein,we report a shape-reconfigurable micropillar array chip for the manipulation of water droplets,oil droplets and water-in-oil droplets.Water-in-oil droplets provide an enclosed space for water droplets,preventing the evaporation in an open environment.Perfluoropolyether coated on the surface of the chip effectively reduces the droplet movement resistance.The micropillar array chip has light and magnetic dual-response due to the Fe3O4 nanoparticles and the reduced iron powder mixed in the shape-memory polymer.The micropillars irradiated by a near-infrared laser bend under the magnetic force,while the unirradiated micropillars still keep their original shape.In the absence of a magnetic field,when the micropillars in a temporary shape are irradiated by the near-infrared laser to the transition temperature,the micropillars return to their initial shape.In this process,the surface morphology gradient caused by the deformation of the micropillars and the surface tension gradient caused by the temperature change jointly produce the driving force of droplet movement.
文摘This paper reviews recent developments in nonlinear control technologies for shape memory alloy (SMA) actuators in robotics and their related applications. SMA possesses large hysteresis, low bandwidth, slow response, and non-linear behavior, which make them difficult to control. The fast response of the SMA actuator mostly depends upon, (1) type of controller, (2) rate of addition and removal of heat, and (3) shape or form of the actuator. Though linear controllers are more desirable than nonlinear ones, the review of literature shows that the results obtained using nonlinear controllers were far better than the former one. Therefore, more emphasis is made on the nonlinear control technologies taking into account the intelligent controllers. Various forms of SMA actuator along with different heating and cooling methods are presented in this review, followed by the nonlinear control methods and the control problems encountered by the researchers.
基金supported in part by the National Key R&D Program of China (No. 2018YFA0306301)the National Natural Science Foundation of China (Nos. 12192252, 62022058, 12074252, and 12004245)+2 种基金the Shanghai Municipal Science and Technology Major Project (No. 2019SHZDZX01ZX06)the Shanghai Rising-Star Program (No. 20QA1405400)the Yangyang Development Fund.
文摘Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus light through inhomogeneous media, which is vital for optical imaging, communication,therapy, etc. Wavefront shaping based on the scattering matrix (SM) is extremely useful in handling dynamicprocesses in the linear regime. However, the implementation of such a method for controlling light in nonlinearmedia is still a challenge and has been unexplored until now. We report a method to determine the SM ofnonlinear scattering media with second-order nonlinearity. We experimentally demonstrate its feasibility inwavefront control and realize focusing of nonlinear signals through strongly scattering quadratic media.Moreover, we show that statistical properties of this SM still follow the random matrix theory. The scattering-matrix approach of nonlinear scattering medium opens a path toward nonlinear signal recovery, nonlinearimaging, microscopic object tracking, and complex environment quantum information processing.
基金This research was supported in part by the National Science Foundation (NSF) Information Technology Research under Grant No.IIS-0082035the NSF under Grant No.IIS-0097646+1 种基金Alfred P.Sloan Fellowship,Honda Initiation Awardan appointment of Haixia Du to the NLM Research Participation Program sponsored by the National Library of Medicine and administered by the Oak Ridge Institute for Science and Education
文摘Shape skeletonization （i.e., medial axis extraction） is powerful in many visual computing applications, such as pattern recognition, object segmentation, registration, and animation. In this paper, the authors expand the use of diffusion equations combined with distance field information to approximate medial axes of arbitrary 3D differential properties. It offers an alternative solids represented by polygonal meshes based on their but natural way for medial axis extraction for commonly used 3D polygonal models. By solving the PDE along time axis, this system can not only quickly extract diffusion-based medial axes of input meshes, but also allow users to visualize the extraction process at each time step. In addition, the proposed model provides users a set of manipulation toolkits to sculpt extracted medial axes, then use diffusion-based techniques to recover corresponding deformed shapes according to the original input datasets. This skeleton-based shape manipulation offers a fast and easy way for animation and deformation of complicated mesh objects.
文摘目的针对摇盖式异形烟盒烟支入盒工艺普遍使用手工包装,导致生产效率低下且易产生二次污染等问题,提出使用真空吸附式机械手完成烟支入盒流程,并对机械手末端真空吸盒的结构进行优化设计。方法应用FLUENT软件对3种不同结构型式真空吸盒的二维流场进行数值模拟分析,得到吸盒端口结构型式及真空度与负压气流场稳定性的影响关系。结果负压气流场稳定性强弱关系为锥形>圆形>方形;随着真空度的增加,吸盒端口中心及吸孔入口流速均增加,负压气流场内真空度越大,其稳定性越差,当真空度分别为20,25,30,40 k Pa时,锥形吸盒气流场的理想真空度为20 k Pa。结论设计的烟支入盒工艺合理,稳定性好,效率高。模拟结果可给真空吸盒的优化设计提供理论依据。
