Sensor-accuracy precision positioning with the existence of static friction part I - dynamic model of friction during the pre-sliding range

Abstract

One of the main difficulties in dealing with precision positioning problems is the friction force and the induced nonlinear behavior existing in the mechanism. In this research, the static friction behavior is observed experimentally for a direct drive torque motor system. It is found that the qualitative behavior of static friction can be summarized in several simple rules. The deformation in stiction phase is the result of two motions: plastic deformation that demonstrates creep and work hardening, and nonlinear spring deformation that demonstrates hysteresis with memory and wipe out effects. It is also found that these phenomena are common to lots of mechanical friction. Furthermore, it is very close to the behavior of a standard plastic solid. A new static friction model that consists of a plastic module and a nonlinear spring module is introduced. This model is of a simple structure and is proved to satisfy all those rules relating to qualitative behavior. Simulation results show that this model does match those experimental results conducted by the authors as well as by other investigators.