A Method for Force Platforms Dynamic Performances Characterization in Clinical Applications

Metrological characterization of Medical Force Platforms is usually limited to their static behavior, as the dynamic analysis is often expensive and time consuming, usually performed by means of very complex and bulky devices. In this study a novel method for the evaluation of the Force Platform dynamic behavior has been proposed by means of a prototypal movable dynamic calibrator, developed in a previous work and that is used to determine five performance indices: Normalized Ratio Bandwidth, Harmonic Distortion, Root Mean Square Trueness, Surface Uniformity, Force uniformity. In particular the dynamic calibrator has been applied to a prototype strain gauges force platform, by loading it on five different points (4 points corresponding to the anterior and rear footing points and the center of the plate) with 3 force amplitudes (400±100 N,700±175 N,900±225N) at 8 frequencies (1, 2, 3, 4, 5, 6, 8, 10 Hz). Finally, the values of the above indices have been processed and plotted in a kiviat chart and compared with the reference values selected by the authors, in order to describe the dynamic performances of the platform in one image. The results showed a nonuniform behavior over the plate footboard, especially in its center, suggesting the need for a perspective in depth study to better evaluate its causes