Dynamic modeling of a scott-russell amplifying mechanism driven by a piezoelectric actuator

The dynamic equations of a micro-positioning Scott-Russell (SR) mechanism associated with two flexible hinges and an offset are developed to calculate the output responses. Both rigid and flexible hinges are considered to explore the results. The manufacturing inaccuracy of the SR mechanism definitely causes geometric offsets of flexure hinges, and affects the displacement amplification and straight-line output motion. Analytical models based on kinematics and Hamilton´s principle are derived to explore the variation of linearity ratio, magnification factor and deviation factor due to various offsets and links´ lengths. It is found that offsets of flexure hinges obviously affect the amplifying factor and linearity ratio, and appear to dominate the changes of magnification factors. Moreover, analytical model is also performed to predict the magnification factors due to various offsets. Finally, some conclusions concerning about the effects of offset on the performance of the SR mechanism are drawn.