Abstract— The out of plane free vibrations of planar parallel cable robots possess a long duration, this is a problem for applications that require a fast settling time, which corresponds to the time necessary for the vibration to stop. We evaluated the effectiveness of a tuned mass damper (TMD) as a solution to minimize the settling time of these nonlinear vibrations. This paper presents a dynamical model of a two degree of freedom nonlinear mechanical system. Using this model, a numerical search was conducted to identify the optimal set of design parameters. During our investigations, it was observed that with an optimized tuned mass damper reductions of 96.51% of the settling time in the best case can be achieved and that the effectiveness of this optimized TMD is relatively homogeneous in the workspace with the exception of the workspace corners.