Structural Design And Analysis Of Microgripper Based On Conical Arc Straight Beam Flexure Hinges

Micro-nano operating systems are widely used in biomedicine,microelectronics,ultra-precision measurement and so on,and play an indispensable role.As the end effector of the micro-nano operating system,the performance of the microgripper directly affects the efficiency and quality of the micro-operation.Aiming at the problems of a single selection of flexure hinges,fixed of clamping end and small range of clamping in the process of microgripper structure design,the paper proposes a conical arc straight beam flexure hinge,establishes the static model of the hinge,and investigates the influence of the parameters of the hinge on the performance of the bridge amplification mechanism.Based on the hinge,a piezoelectric actuated one degree of freedom microgripper is designed,the specific research content is as follows:Based on the generalized equation for conic curves in polar coordinates,a conical arc straight beam flexure hinge is proposed,and establishes the static model,deduces the flexibility matrix expression.The correctness of the model is verified by finite element simulation and experiment.Based on the conical curved straight beam flexure hinges,matrix-based compliance modeling(MCM)method is adopted to establish the static model of the bridge amplification mechanism.The variation of displacement magnification,input and output stiffness of bridge amplification mechanism with size parameters is studied.Based on the conical arc straight beam flexure hinges and bridge amplification mechanism,a piezoelectric actuated one degree of freedom microgripper is designed.By connecting the bridge amplification mechanism,L-shaped lever mechanism and parallel quadrilateral lever mechanism in series,to make microgripper has a larger displacement amplification ratio.MCM method is adopted to carry out the kinematic and static analysis of the microgripper.The displacement amplification factor,the input stiffness and the coupling relationship between the parasitic displacement and the expected displacement of the microgripper are studied.The response surface model between the size parameters of the microgripper and its performance is established and study the influence of the size parameters on its performance.The optimization algorithm is adopted to determine the dimension parameters of the microgripper.The finite element model of the microgripper is established,and the static and dynamic characteristics of the microgripper are analyzed by statics and modal simulation,which verifies the correctness of the theoretical model.The performance testing system of the microgripper is established.Through the displacement characteristic experiment,the displacement magnification of the microgripper is determined to be 21.68,and the effect of hysteresis characteristics of piezoelectric actuator on output displacement of microgripper is studied.The first two natural frequencies of the microgripper are determined by sweeping experiments,which are 457.5 Hz and 797.5 Hz,respectively.Based on PID displacement controller,closedloop control experiment is carried out.Through the cell micro-operating system,operations such as clamping,moving and releasing of human lung adenocarcinoma cells are realized.