Kinematic characteristic analysis of a micro-/nano positioning stage based on bridge-type amplifier

The piezo-actuated micro-/nano positioning stage based on bridge-type amplifier is frequently designed and used in the current precision engineering applications. The displacement amplification ratio of displacement amplifier is vital for kinematic performance of a positioning stage. Based on the force analysis during the deformation process of bridge-type amplifier, an improved analytical model of the displacement amplification ratio is derived by employing the energy principle and the elastic beam theory to obtain a better prediction accuracy. After the comparisons with the existing analytical models and finite element analysis (FEA) results, the proposed model is proved has higher prediction accuracy than existing models, especially when the displacement amplification ratio changes with the interval of two adjacent flexure hinges. Based on proposed displacement amplification model for bridge-type amplifier, a kinematic model for a positioning stage is carried out by considering the structural stiffness of the positioning stage. Moreover, the two resistance factors are defined to calculate quantitatively the attenuated output displacement of piezoelectric actuator (PZA) and bridge-type amplifier in positioning systems. The correctness of the proposed theoretical model is verified by FEA and experiments, which indicates that the attenuation ratio of output displacement of the positioning stage up to a maximum of 58.76%.