Effects of Surface Topography on Non-Steady Lubricated Frictional Contacts

Modern machines depend on high-speed and high accuracy motion control for achieving their intended task. Friction however has a sever effect on system performance (e.g. accuracy) by its negative side effects, like energy losses and non-linear behavior (e.g. stick-slip phenomena). Previous research was focused either on reducing the Coefficients Of Friction to increase energy efficiency or on modeling the non-steady behavior of friction and taking them into account in the control loop. Multiple advanced behavioral friction models where developed (LuGre, Leuven, …) to describe friction instabilities. System engineers use complicated estimators to identify the model parameters to cope with this friction in their application. A paradigm shift is required towards adapting the frictional behavior to the system requirements.  
The results of past research indicates the role of surface topography on the static and kinetic friction coefficients of dry and lubricated contacts, although the influence on the non-linear frictional behavior is left aside. In this PhD numerical and experimental work is conducted to assess the influence of surface topography on the frictional instability of lubricated metallic surfaces. The outcome should lead to upfront describing and engineering the non-steady friction