Nonlinear modeling and evaluation of rolling friction

This paper presents a nonlinear friction modeling and its evaluation for rolling friction behaviors in ball screw-driven table systems. The rolling friction behaves as a nonlinear component in the table drive mechanism, especially in the micro-displacement region, deteriorating the control performance in the fine positioning. The friction characteristic, therefore, should be clarified to provide the precise mathematical simulator and to design the effective compensators. In the friction modeling, the characteristics of rolling friction, which are depending on the displacement region, are especially paid attention: In ldquostarting rolling displacement regionrdquo, the friction force dynamically varies for the displacement after velocity reversal. In ldquorolling regionrdquo, on the other hand, the friction force statically indicates the Coulomb friction. Based on the nonlinear behaviors, the rolling friction can be mathematically modeled, and the rolling friction model can express both the dynamic and static characteristics of friction after the reversal. The proposed nonlinear modeling of the rolling friction has been evaluated in both frequency and time domains using a prototype for industrial positioning devices.