Design And Analysis Of Flexure-based Microgripper

The rapid development of micro/nano technology proposed a higher demand for micromanipulator, and that promotes the research of micromanipulation robot. Micromanipulator dimensions do not have to be too small, but it can achieve micron or nanometer level precision movement and operation. And it can play an important role in precision mechanical engineering, microelectronic assembly, micro-nano processing, genetic engineering, fiber butt, minimally invasive surgery and other fields. The flexible microgripper, driven by piezoelectric actuator(PZT), is a typical execution ends of micro-assembly systems.it has the advantages of a compact structure, convenience to machine, easily control, etc, so that it become the hot spot at home and abroad. Therefore, making research about the microgripper with large displacement output, compact, easy to control, has far-reaching significance on promoting the development of sophisticated technology.This paper is supported by the Independent Research Fund of State Key Laboratory of Mechanical Transmission and the Open Foundation of Shang Hai Key Laboratory of Spacecraft Mechanism. Based on easily to control and large jaw displacement, a micro gripper with three-stage amplification is designed innovatively. Structural design, static analysis, machining and testing were researched about the micro gripper. The main research contents are as follows:Based on compliant mechanism, precision instrument design, mechanical principle, Castigliano’s theorem and mechanics of materials, the composition and working principle compliant mechanism was studied and a micro gripper with three-stage amplification was designed. The input/output stiffness of the bridge type amplification mechanism(BTAM) are deduced.Using of pseudo-rigid-body method, free body diagram method and virtual work principle, the pseudo-rigid-body(PRB) model of micro/nano transmission platform and micro gripper were established. the force situation of lever and parallel guide mechanism(PGM) were analyzed. The stiffness mode of leverage-parallel guide mechanism its displacement magnification ratio were deduced. the relationship between clamping force and the input force was determined.In terms of bond graph theory, the bond graph models of typical components of compliant mechanism were comprehensively analyzed. the laws of motion of micro/nano transmission platform and micro gripper were revealed, energy transfer form of BTAM and PGM were reaserched, the bond graph models of platform and micro gripper were derived, the characteristic equations and State-Space equations were derived.The processing method and material selection principle of compliant mechanisms were analyzed, and the micro gripper was machined by laser rapid prototyping technology(3D print), the State-Space equations of platform and micro gripper were solved by Matlab/Simulink, the displacement simulation curves were obtained, the micro gripper test apparatus were set, the input and output performance of microgripper obtained, The bond graphs model built to analyze compliant mechanism is proved, the practical engineering application of micro gripper is described by combining with micro operating system.