A new precise actuator is proposed,which is ac-tuated by the impact force of an end-loaded piezoelectric bimorph cantilever,and bears two degrees of freedom for translation and rotation.The dynamic characteristics of ...A new precise actuator is proposed,which is ac-tuated by the impact force of an end-loaded piezoelectric bimorph cantilever,and bears two degrees of freedom for translation and rotation.The dynamic characteristics of the piezoelectric bimorph were analyzed by FEM,and are fur-ther proved by experimental tests.A new control system for the actuator was put forward and tested,which is called the fixed-frequency with adjustable voltage.In addition,the actuator’s performance of translation and rotation were both measured.The results demonstrate that the actuator is char-acterized by a simple structure,large movement range,strong driving ability and high positioning resolution.Its cost is estimated at only 1%of the traditional impact actuators.展开更多
Precision motion actuation is a key technology for miniature medical robotics in a variety of applications,such as optical fibre-based diagnosis and intervention tools.Conventional inductive actuation mechanisms are c...Precision motion actuation is a key technology for miniature medical robotics in a variety of applications,such as optical fibre-based diagnosis and intervention tools.Conventional inductive actuation mechanisms are challenging to scale down.Piezoelectric materials offer a scalable,precise,fast and high-force method but at a limited displacement range.In previous work,the combination of piezoelectric beams(benders)with compliant motion translation structures has been shown to be promising for robotic micro-actuation.In this paper,this approach is employed to implement a three degrees of freedom delta robot,suitable for catheter,diagnostic optical fibre and microsurgery tool manipulation.The fabrication process combines additive manufacturing,origami structuring and piezoelectric beam assembly.Closed-loop control is implemented using a new,on-board visual feedback concept.In contrast to typical optical motion systems,the fully internal visual feedback offers system compactness with precise and reliable camera-to-marker geometry definition.By employment of this method,a delta robot with motion accuracy of 7.5μm,resolution of 10μm and 8.1μm precision is demonstrated.The robot is shown to follow a range of programmable trajectories under these specifications,and to compensate for externally applied forces typically expected during microsurgery manipulations.This is the first,to our knowledge,demonstration of micromotion control using internal visual feedback,and it opens up the way for high-resolution compact microrobots.展开更多
Designing artificial structures with heterogeneous elements and manipulating their interface coupling ways usually bring in synthetic neo-nature to functional devices.For piezoceramic devices,the deformation response ...Designing artificial structures with heterogeneous elements and manipulating their interface coupling ways usually bring in synthetic neo-nature to functional devices.For piezoceramic devices,the deformation response refers to a variety of extensional,contractional,or shear modes of crystals,and also relies on boundary conditions from morphology design.However,to pursue fundamental torsion actuation in an integrated piezoceramic component is still a long-term tough task due to nil twist mode limited by microscopic crystal mirror symmetry.Herein,we demonstrate a design of cofired monolithic actuators to originally overcome this obstacle.The prototype device is composed of two sets of stacked actuation subunits that work on artificially reverse face shear modes,and their chiral stiffness couplings will synergistically contribute to synthetic twist outputs at a broad bandwidth.Finite element simulation reveals twist displacements are highly tunable by manipulating the geometrical dimensions.Transverse deflection measurements manifest the stable and sizeable linear actuation response to applied electric fields(around 3.7μm under 40 V at 1 Hz).Importantly,the design actually introduces a more general route to enable arbitrary modes and actuation states in integrated piezoceramic components.展开更多
文摘A new precise actuator is proposed,which is ac-tuated by the impact force of an end-loaded piezoelectric bimorph cantilever,and bears two degrees of freedom for translation and rotation.The dynamic characteristics of the piezoelectric bimorph were analyzed by FEM,and are fur-ther proved by experimental tests.A new control system for the actuator was put forward and tested,which is called the fixed-frequency with adjustable voltage.In addition,the actuator’s performance of translation and rotation were both measured.The results demonstrate that the actuator is char-acterized by a simple structure,large movement range,strong driving ability and high positioning resolution.Its cost is estimated at only 1%of the traditional impact actuators.
基金financially supported in part by the Engineering and Physical Sciences Research Council(EPSRC),United Kingdom(EP/P012779,Micro-Robotics for Surgery).
文摘Precision motion actuation is a key technology for miniature medical robotics in a variety of applications,such as optical fibre-based diagnosis and intervention tools.Conventional inductive actuation mechanisms are challenging to scale down.Piezoelectric materials offer a scalable,precise,fast and high-force method but at a limited displacement range.In previous work,the combination of piezoelectric beams(benders)with compliant motion translation structures has been shown to be promising for robotic micro-actuation.In this paper,this approach is employed to implement a three degrees of freedom delta robot,suitable for catheter,diagnostic optical fibre and microsurgery tool manipulation.The fabrication process combines additive manufacturing,origami structuring and piezoelectric beam assembly.Closed-loop control is implemented using a new,on-board visual feedback concept.In contrast to typical optical motion systems,the fully internal visual feedback offers system compactness with precise and reliable camera-to-marker geometry definition.By employment of this method,a delta robot with motion accuracy of 7.5μm,resolution of 10μm and 8.1μm precision is demonstrated.The robot is shown to follow a range of programmable trajectories under these specifications,and to compensate for externally applied forces typically expected during microsurgery manipulations.This is the first,to our knowledge,demonstration of micromotion control using internal visual feedback,and it opens up the way for high-resolution compact microrobots.
基金the National Natural Science Foundation of China(51772005,51132001,and 52032012)Beijing Key Laboratory for Magnetoelectric Materials and Devices。
文摘Designing artificial structures with heterogeneous elements and manipulating their interface coupling ways usually bring in synthetic neo-nature to functional devices.For piezoceramic devices,the deformation response refers to a variety of extensional,contractional,or shear modes of crystals,and also relies on boundary conditions from morphology design.However,to pursue fundamental torsion actuation in an integrated piezoceramic component is still a long-term tough task due to nil twist mode limited by microscopic crystal mirror symmetry.Herein,we demonstrate a design of cofired monolithic actuators to originally overcome this obstacle.The prototype device is composed of two sets of stacked actuation subunits that work on artificially reverse face shear modes,and their chiral stiffness couplings will synergistically contribute to synthetic twist outputs at a broad bandwidth.Finite element simulation reveals twist displacements are highly tunable by manipulating the geometrical dimensions.Transverse deflection measurements manifest the stable and sizeable linear actuation response to applied electric fields(around 3.7μm under 40 V at 1 Hz).Importantly,the design actually introduces a more general route to enable arbitrary modes and actuation states in integrated piezoceramic components.
