Multi-material 3D fabrication at the nanoscale has been a long-sought goal in additive manufacturing,with great potential for the direct construction of functional micro/nanosystems rather than just arbitrary 3D struc...Multi-material 3D fabrication at the nanoscale has been a long-sought goal in additive manufacturing,with great potential for the direct construction of functional micro/nanosystems rather than just arbitrary 3D structures.To achieve this goal,researchers have introduced several nanoscale 3D printing principles,explored various multi-material switching and combination strategies,and demonstrated their potential applications in 3D integrated circuits,optoelectronics,biological devices,micro/nanorobots,etc.Although some progress has been made,it is still at the primary stage,and a serious breakthrough is needed to directly construct functional micro/nano systems.In this perspective,the development,current status and prospects of multi-material 3D nanoprinting are presented.We envision that this 3D printing will unlock innovative solutions and make significant contributions to various technologies and industries in the near future.展开更多
A robust adaptive controller for a nonholonomic mobile robot with unknown kinematic and dynamic parameters is proposed. A kinematic controller whose output is the input of the relevant dynamic controller is provided b...A robust adaptive controller for a nonholonomic mobile robot with unknown kinematic and dynamic parameters is proposed. A kinematic controller whose output is the input of the relevant dynamic controller is provided by using the concept of backstepping. An adaptive algorithm is developed in the kinematic controller to approximate the unknown kinematic parameters, and a simple single-layer neural network is used to express the highly nonlinear robot dynamics in terms of the known and unknown parameters. In order to attenuate the effects of the uncertainties and disturbances on tracking performance, a sliding mode control term is added to the dynamic controller. In the deterministic design of feedback controllers for the uncertain dynamic systems, upper bounds on the norm of the uncertainties are an important clue to guarantee the stability of the closed-loop system. However, sometimes these upper bounds may not be easily obtained because of the complexity of the structure of the uncertainties. Thereby, simple adaptation laws are proposed to approximate upper bounds on the norm of the uncertainties to address this problem. The stability of the proposed control system is shown through the Lyapunov method. Lastly, a design example for a mobile robot with two actuated wheels is provided and the feasibility of the controller is demonstrated by numerical simulations.展开更多
Large,3D curved electronics are a trend of the microelectronic industry due to their unique ability to conformally coexist with complex surfaces while retaining the electronic functions of 2D planar integrated circuit...Large,3D curved electronics are a trend of the microelectronic industry due to their unique ability to conformally coexist with complex surfaces while retaining the electronic functions of 2D planar integrated circuit technologies.However,these curved electronics present great challenges to the fabrication processes.Here,we propose a reconfigurable,mask-free,conformal fabrication strategy with a robot-like system,called robotized‘transfer-and-jet’printing,to assemble diverse electronic devices on complex surfaces.This novel method is a ground-breaking advance with the unique capability to integrate rigid chips,flexible electronics,and conformal circuits on complex surfaces.Critically,each process,including transfer printing,inkjet printing,and plasma treating,are mask-free,digitalized,and programmable.The robotization techniques,including measurement,surface reconstruction and localization,and path programming,break through the fundamental constraints of 2D planar microfabrication in the context of geometric shape and size.The transfer printing begins with the laser lift-off of rigid chips or flexible electronics from donor substrates,which are then transferred onto a curved surface via a dexterous robotic palm.Then the robotic electrohydrodynamic printing directly writes submicrometer structures on the curved surface.Their permutation and combination allow versatile conformal microfabrication.Finally,robotized hybrid printing is utilized to successfully fabricate a conformal heater and antenna on a spherical surface and a flexible smart sensing skin on a winged model,where the curved circuit,flexible capacitive and piezoelectric sensor arrays,and rigid digital–analog conversion chips are assembled.Robotized hybrid printing is an innovative printing technology,enabling additive,noncontact and digital microfabrication for 3D curved electronics.展开更多
Motion control of the human hand is the most complex part of the human body.It has always been a challenge for a good balance between the cost,weight,responding speed,grasping force,finger extension,and dexterity of p...Motion control of the human hand is the most complex part of the human body.It has always been a challenge for a good balance between the cost,weight,responding speed,grasping force,finger extension,and dexterity of prosthetic hand.To solve these issues,a 3D-printed cable driven humanoid hand based on bidirectional elastomeric passive transmission(BEPT)is designed in this paper.A semi-static model of BEPT is investigated based on energy conservation law to analyze the mechanical properties of BEPT and a dynamical simulation of finger grasping is conducted.For a good imitation of human hand and an excellent grasping performance,specific BEPT is selected according to human finger grasping experiments.The advantage of BEPT based humanoid hand is that a good balance between the price and performance of the humanoid hand is achieved.Experiments proved that the designed prosthetic hand’s single fingertip force can reach 33 N and the fastest fingertip grasping speed realized 0.6 s/180°.It also has a good force compliance effect with only 430g’s weight.It can not only grab fragile objects like raw eggs and paper cup,but also achieve strong grasping force to damage metal cans.This humanoid hand has considerable application prospects in artificial prosthesis,human-computer interaction,and robot operation.展开更多
The recently developed hard-magnetic soft(HMS)materials manufactured by embedding high-coercivity micro-particles into soft matrices have received considerable attention from researchers in diverse fields,e.g.,soft ro...The recently developed hard-magnetic soft(HMS)materials manufactured by embedding high-coercivity micro-particles into soft matrices have received considerable attention from researchers in diverse fields,e.g.,soft robotics,flexible electronics,and biomedicine.Theoretical investigations on large deformations of HMS structures are significant foundations of their applications.This work is devoted to developing a powerful theoretical tool for modeling and computing the complicated nonplanar deformations of flexible beams.A so-called quaternion beam model is proposed to break the singularity limitation of the existing geometrically exact(GE)beam model.The singularity-free governing equations for the three-dimensional(3D)large deformations of an HMS beam are first derived,and then solved with the Galerkin discretization method and the trustregion-dogleg iterative algorithm.The correctness of this new model and the utilized algorithms is verified by comparing the present results with the previous ones.The superiority of a quaternion beam model in calculating the complicated large deformations of a flexible beam is shown through several benchmark examples.It is found that the purpose of the HMS beam deformation is to eliminate the direction deviation between the residual magnetization and the applied magnetic field.The proposed new model and the revealed mechanism are supposed to be useful for guiding the engineering applications of flexible structures.展开更多
Electrohydrodynamic(EHD)printing technique,which deposits micro/nanostructures through high electric force,has recently attracted significant research interest owing to their fascinating characteristics in high resolu...Electrohydrodynamic(EHD)printing technique,which deposits micro/nanostructures through high electric force,has recently attracted significant research interest owing to their fascinating characteristics in high resolution(<1μm),wide material applicability(ink viscosity 1–10000 cps),tunable printing modes(electrospray,electrospinning,and EHD jet printing),and compatibility with flexible/wearable applications.Since the laboratory level of the EHD printed electronics'resolution and efficiency is gradually approaching the commercial application level,an urgent need for developing EHD technique from laboratory into industrialization have been put forward.Herein,we first discuss the EHD printing technique,including the ink design,droplet formation,and key technologies for promoting printing efficiency/accuracy.Then we summarize the recent progress of EHD printing in fabrication of displays,organic field-effect transistors(OFETs),transparent electrodes,and sensors and actuators.Finally,a brief summary and the outlook for future research effort are presented.展开更多
Electrohydrodynamic(EHD)printing has critical merits in micro/nanoscale additive manufacturing because of its ultrahigh resolution and wide ink compatibility,making it an advantageous choice for electronics manufactur...Electrohydrodynamic(EHD)printing has critical merits in micro/nanoscale additive manufacturing because of its ultrahigh resolution and wide ink compatibility,making it an advantageous choice for electronics manufacturing,high-resolution prototyping,and biological component fabrication.However,EHD printing is currently limited by its rather low throughput due to the lack of high-frequency and high-density multi-nozzle printheads.This paper presents a novel EHD printhead with a protruding polymer-based nozzle design.An insulated,hydrophobic,and protruding polymer nozzle array with an appropriate geometric structure can effectively address key problems in multi-nozzle jetting,such as electrical crosstalk,electrical discharge,liquid flooding,and nonuniform jetting.By investigating the influence of the electrical and geometric characteristics of the nozzle arrays on the electrical crosstalk behavior and fabricating the optimized nozzle array via MEMS technology,we achieve an EHD printhead with a large scale(256),high density(127 dpi),and high jetting frequency(23 kHz),and addressable jetting can be realized by adding independently controllable extractors underneath the nozzle array.Many functional materials,such as quantum dots,perovskite,and nanosilver inks,can be ejected into high-resolution patterns through the optimized nozzle array,demonstrating the great prospects of our designed printhead in electronics manufacturing.This MEMS-compatible printhead design lays the foundation for high-throughput fabrication of micro/nanostructures and promotes practical applications of EHD printing in functional electronics and biomedical/energy devices.展开更多
基金financially National Natural Science Foundation of China(Nos.52075209 and 51925503)Natural Science Foundation for Distinguished Young Scholars of Hubei province of China(No.2022CFA066)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2021QNRC001)。
文摘Multi-material 3D fabrication at the nanoscale has been a long-sought goal in additive manufacturing,with great potential for the direct construction of functional micro/nanosystems rather than just arbitrary 3D structures.To achieve this goal,researchers have introduced several nanoscale 3D printing principles,explored various multi-material switching and combination strategies,and demonstrated their potential applications in 3D integrated circuits,optoelectronics,biological devices,micro/nanorobots,etc.Although some progress has been made,it is still at the primary stage,and a serious breakthrough is needed to directly construct functional micro/nano systems.In this perspective,the development,current status and prospects of multi-material 3D nanoprinting are presented.We envision that this 3D printing will unlock innovative solutions and make significant contributions to various technologies and industries in the near future.
基金partly supported by the National Natural Science Foundation of China (No.50625516)the 863 program of China(No.2006AA09Z203,2006AA04A110)
文摘A robust adaptive controller for a nonholonomic mobile robot with unknown kinematic and dynamic parameters is proposed. A kinematic controller whose output is the input of the relevant dynamic controller is provided by using the concept of backstepping. An adaptive algorithm is developed in the kinematic controller to approximate the unknown kinematic parameters, and a simple single-layer neural network is used to express the highly nonlinear robot dynamics in terms of the known and unknown parameters. In order to attenuate the effects of the uncertainties and disturbances on tracking performance, a sliding mode control term is added to the dynamic controller. In the deterministic design of feedback controllers for the uncertain dynamic systems, upper bounds on the norm of the uncertainties are an important clue to guarantee the stability of the closed-loop system. However, sometimes these upper bounds may not be easily obtained because of the complexity of the structure of the uncertainties. Thereby, simple adaptation laws are proposed to approximate upper bounds on the norm of the uncertainties to address this problem. The stability of the proposed control system is shown through the Lyapunov method. Lastly, a design example for a mobile robot with two actuated wheels is provided and the feasibility of the controller is demonstrated by numerical simulations.
基金The authors acknowledge support from the National Nat-ural Science Foundation of China(51635007,51925503,51705179)Natural Science Foundation of Hubei Province of China(2020CFA028).
文摘Large,3D curved electronics are a trend of the microelectronic industry due to their unique ability to conformally coexist with complex surfaces while retaining the electronic functions of 2D planar integrated circuit technologies.However,these curved electronics present great challenges to the fabrication processes.Here,we propose a reconfigurable,mask-free,conformal fabrication strategy with a robot-like system,called robotized‘transfer-and-jet’printing,to assemble diverse electronic devices on complex surfaces.This novel method is a ground-breaking advance with the unique capability to integrate rigid chips,flexible electronics,and conformal circuits on complex surfaces.Critically,each process,including transfer printing,inkjet printing,and plasma treating,are mask-free,digitalized,and programmable.The robotization techniques,including measurement,surface reconstruction and localization,and path programming,break through the fundamental constraints of 2D planar microfabrication in the context of geometric shape and size.The transfer printing begins with the laser lift-off of rigid chips or flexible electronics from donor substrates,which are then transferred onto a curved surface via a dexterous robotic palm.Then the robotic electrohydrodynamic printing directly writes submicrometer structures on the curved surface.Their permutation and combination allow versatile conformal microfabrication.Finally,robotized hybrid printing is utilized to successfully fabricate a conformal heater and antenna on a spherical surface and a flexible smart sensing skin on a winged model,where the curved circuit,flexible capacitive and piezoelectric sensor arrays,and rigid digital–analog conversion chips are assembled.Robotized hybrid printing is an innovative printing technology,enabling additive,noncontact and digital microfabrication for 3D curved electronics.
基金Supported by National Natural Science Foundation of China(Grant No.91948301)Hubei Provincial Technology Innovation Project of China(Grant No.2019AAA071)Open Fund of State Key Laboratory of Robotics and System(Grant No.SKLRS-2019-KF-11).
文摘Motion control of the human hand is the most complex part of the human body.It has always been a challenge for a good balance between the cost,weight,responding speed,grasping force,finger extension,and dexterity of prosthetic hand.To solve these issues,a 3D-printed cable driven humanoid hand based on bidirectional elastomeric passive transmission(BEPT)is designed in this paper.A semi-static model of BEPT is investigated based on energy conservation law to analyze the mechanical properties of BEPT and a dynamical simulation of finger grasping is conducted.For a good imitation of human hand and an excellent grasping performance,specific BEPT is selected according to human finger grasping experiments.The advantage of BEPT based humanoid hand is that a good balance between the price and performance of the humanoid hand is achieved.Experiments proved that the designed prosthetic hand’s single fingertip force can reach 33 N and the fastest fingertip grasping speed realized 0.6 s/180°.It also has a good force compliance effect with only 430g’s weight.It can not only grab fragile objects like raw eggs and paper cup,but also achieve strong grasping force to damage metal cans.This humanoid hand has considerable application prospects in artificial prosthesis,human-computer interaction,and robot operation.
基金Project supported by the National Key Research and Development Program of China(No.2018YFA0703200)the National Natural Science Foundation of China(Nos.52205594 and51820105008)+1 种基金the China National Postdoctoral Program for Innovative Talents(No.BX20220118)the China Postdoctoral Science Foundation(No.2021M701306)。
文摘The recently developed hard-magnetic soft(HMS)materials manufactured by embedding high-coercivity micro-particles into soft matrices have received considerable attention from researchers in diverse fields,e.g.,soft robotics,flexible electronics,and biomedicine.Theoretical investigations on large deformations of HMS structures are significant foundations of their applications.This work is devoted to developing a powerful theoretical tool for modeling and computing the complicated nonplanar deformations of flexible beams.A so-called quaternion beam model is proposed to break the singularity limitation of the existing geometrically exact(GE)beam model.The singularity-free governing equations for the three-dimensional(3D)large deformations of an HMS beam are first derived,and then solved with the Galerkin discretization method and the trustregion-dogleg iterative algorithm.The correctness of this new model and the utilized algorithms is verified by comparing the present results with the previous ones.The superiority of a quaternion beam model in calculating the complicated large deformations of a flexible beam is shown through several benchmark examples.It is found that the purpose of the HMS beam deformation is to eliminate the direction deviation between the residual magnetization and the applied magnetic field.The proposed new model and the revealed mechanism are supposed to be useful for guiding the engineering applications of flexible structures.
基金National Key Research and Development Program of China,Grant/Award Number:2018YFA0703200National Natural Science Foundation of China,Grant/Award Number:52075209+1 种基金Innovation Project of Optics Valley Laboratory,Grant/Award Number:OVL2021BG007Natural Science Foundation for Distinguished Young Scholars of Hubei province of China,Grant/Award Number:2022CFA066。
文摘Electrohydrodynamic(EHD)printing technique,which deposits micro/nanostructures through high electric force,has recently attracted significant research interest owing to their fascinating characteristics in high resolution(<1μm),wide material applicability(ink viscosity 1–10000 cps),tunable printing modes(electrospray,electrospinning,and EHD jet printing),and compatibility with flexible/wearable applications.Since the laboratory level of the EHD printed electronics'resolution and efficiency is gradually approaching the commercial application level,an urgent need for developing EHD technique from laboratory into industrialization have been put forward.Herein,we first discuss the EHD printing technique,including the ink design,droplet formation,and key technologies for promoting printing efficiency/accuracy.Then we summarize the recent progress of EHD printing in fabrication of displays,organic field-effect transistors(OFETs),transparent electrodes,and sensors and actuators.Finally,a brief summary and the outlook for future research effort are presented.
基金financially supported by the National Natural Science Foundation of China(52075209)the Natural Science Foundation for Distinguished Young Scholars of Hubei Province of China(2022CFA066)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(2021QNRC001)。
文摘Electrohydrodynamic(EHD)printing has critical merits in micro/nanoscale additive manufacturing because of its ultrahigh resolution and wide ink compatibility,making it an advantageous choice for electronics manufacturing,high-resolution prototyping,and biological component fabrication.However,EHD printing is currently limited by its rather low throughput due to the lack of high-frequency and high-density multi-nozzle printheads.This paper presents a novel EHD printhead with a protruding polymer-based nozzle design.An insulated,hydrophobic,and protruding polymer nozzle array with an appropriate geometric structure can effectively address key problems in multi-nozzle jetting,such as electrical crosstalk,electrical discharge,liquid flooding,and nonuniform jetting.By investigating the influence of the electrical and geometric characteristics of the nozzle arrays on the electrical crosstalk behavior and fabricating the optimized nozzle array via MEMS technology,we achieve an EHD printhead with a large scale(256),high density(127 dpi),and high jetting frequency(23 kHz),and addressable jetting can be realized by adding independently controllable extractors underneath the nozzle array.Many functional materials,such as quantum dots,perovskite,and nanosilver inks,can be ejected into high-resolution patterns through the optimized nozzle array,demonstrating the great prospects of our designed printhead in electronics manufacturing.This MEMS-compatible printhead design lays the foundation for high-throughput fabrication of micro/nanostructures and promotes practical applications of EHD printing in functional electronics and biomedical/energy devices.
