Abstract:The micro gripper requires large stroke and low coupling. To fulfil these requirements, a novel flexurebased micro gripper is designed with threestage amplifier. The bridgetype mechanism and levertype mechanism are also utilized. Based on the principle of flexible mechanics, elastic mechanics and dynamics, the dynamic features of micro gripper are improved by optimizing the fixed position of the bridgetype mechanism. Moreover, the theoretical displacement amplification model, coupling error model and dynamic model of micro gripper are formulated. The output displacement feature and dynamic feature of the micro gripper are obtained. The micro gripper is manufactured by the combination of 3D printing and wire cut electrical discharge machining. The correctness of the theoretical model is verified by comparing the theoretical, simulation and experimental data. The displacement amplification of the proposed micro gripper is 197, and the natural frequency is 223 Hz. All the errors with experimental data fluctuate within 10%. The working stroke of micro gripper is 750 μm while the coupling error is only 035% within the working stroke. The micro gripper has the features of large stroke, high precision, low coupling and good dynamics.