A Generalized Mathematical Model for the Bridge-Type and Lever-Type Mechanism

The bridge-type amplifier and the lever-type amplifier are the two frequently used displacement amplifiers in the precision engineering. However, to the knowledge of the authors, a generalized mathematical model appropriate for the both types mechanism was not frequently reported, which is instrumental in selecting and designing of the displacement amplifiers in the practice application. To this end, the compliance matrix method based on screw theory is employed to establish a generalized mathematical model for the two amplifiers to offer an easy and objective way to analyze them. In addition, the performances of the amplifiers under external loads are presented in this paper. Theoretical and finite elemental analysis results shown that the prediction errors of the established model for the displacement amplification ratio is within 4.5%, which is so accurate to predict the performance of the two kinds of amplifiers. Finally, the analytical model are confirmed by finite element analysis and by experimental testing of a bridge-lever-type amplifier.