Friction modeling of a high-precision positioning system using linear permanent magnet synchronous motors is investigated. The friction force is measured precisely by some specific experiments to eliminate the parasitic ripple force. The experimental data show that the relation between the lubrication force and the velocity is not linear as it is assumed in the conventional friction models used in automatic control. A new model for the lubrication force based on tribological observations is proposed and introduced to the LuGre friction model. The new model can characterize the lubrication force saturation which is encountered in the acquired data. The parameters of the new friction model are identified and compared with the standard ones.