The article deals with the application of force sensors to estimate position error of center of mass of the mobile platform of a cable-driven parallel robot. Conditions of deformations of cables and towers of the robot are included in the numerical model and some external disturbances are included too. A method of estimation of the error in positioning via force sensors is sensitive to the magnitude of spatial oscillations of the mobile platform. To reduce torsional vibrations of the mobile platform around vertical axis dynamic damper has been included into the system.