On the Static Stiffness of Incompletely Restrained Cable-Driven Robot

The static stiffness of incompletely restrainedLiHui@Li, Hui cable-driven robot (IRCR) is studied and its theoretical formulation of the calculation model is derived. The analysis shows that the static stiffness matrix is a sum of two components. The first part \(\mathbf{{K}}_{1}\) results from the change of position and orientation of end-effector which is proportional to cable tensions, while the second \(\mathbf{{K}}_{2}\) is caused by the deformation and deflection of cables. The study shows that \(\mathbf{{K}}_{2}\) is not only affected by material performances of all cables but by cable tensions. For the IRCR, however, the static stiffness correlates both parts because of the existence of cable catenaries. Two examples concerning the static stiffness are given for verification. Finally a few improvements are proposed for robot design based on stiffness analysis.