Novel mechanically fully decoupled six-axis force-moment sensor

In this study, a novel six-axis force/moment (F/M) sensor was developed. The sensor has a novel ring structure comprising a cross-beam elastic body with sliding and rotating mechanisms to achieve complete decoupling. The unique sliding and rotating mechanisms can reduce cross-talk effects caused by minimized structural interconnection. The forces F_x, F_y, and F_z and moments M_x, M_y, and M_z can be measured for the six-axis F/M sensors according to the elastic deformation of strain gauges attached to the cross beam. Herein, we provide detailed descriptions of the mathematical models, model idealizations, model creation, and the mechanical decoupling principle. The paper also presents a theoretical analysis of the strain based on Timoshenko beam theory and the subsequent validation of the analysis results through a comparison of the results with those obtained from a numerical analysis conducted using finite element analysis simulations. The sensor was subjected to experimental testing to obtain the maximum cross-talk errors along the following six axes under different loadings (the errors are presented in parentheses): F_x under SM_y (2.12%), F_y under SM_x (1.88%), F_z under SM_z (2.02%), M_x under SF_z (1.15%), M_y under SF_x (1.80%), and M_z under SF_x (2.63%). The proposed sensor demonstrated a considerably improved cross-talk error performance compared with existing force sensors.