EXPERIMENTAL MODAL ANALYSIS OF FLEXIBLE LINKAGES IN A “SMART PARALLEL PLATFORM”

A lightweight “smart parallel platform ” is proposed to actively suppress unwanted linkage vibration in a planar parallel mechanism using smart components. In order to design efficient vibration control laws in modal space, a dynamic model of flexible linkages in the modal domain is developed through experimental modal identification using the combination of a hammer, an accelerometer and Lead Zirconate Titanate (PZT) transducers. The Global Rational Fraction Polynomial (GRFP) method using orthogonal polynomials is briefly reviewed and Frequency Response Function (FRF) formulations for PZT transducers are derived. This procedure is applied to the smart parallel platform with PZT components. Mode shapes identified using PZT transducers are consistent with those obtained from the hammer-accelerometer test. Configuration dependent influence of rigid body motion on flexible motion is also analyzed. Conclusions for active vibration control design are drawn from analysis of experimental results. 1