Flexure design for precision positioning using low-stiffness actuators

This paper analytically investigates flexures to mechanically guide the moving part of a precision positioning system actuated by Lorentz actuators, where the control bandwidth is typically restricted by the second or higher mechanical resonances that can include internal modes of the positioning mass. Based on analytical models, mechanical resonant frequencies are derived for a given set of parameters to determine flexure dimensions and material. As a result of the derivation and analysis, a model is proposed to predict this second resonant frequency for a given first resonant frequency to achieve better control design and performance. As the verification, the effectiveness of the proposed model is confirmed by using Finite Element Analysis (FEA), as well as an experimental setup for frequency response.